Aeration Alleviated the Adverse Effects of Nitrogen Topdressing Reduction on Tomato Root Vigor, Photosynthetic Performance, and Fruit Development.

To explore the compensation effect of aeration on tomato vegetative and reproductive growth in arid and semi-arid areas, a two-year field experiment was conducted with four micro-nano aeration ratios (0%, 5%, 10%, and 15%) and three nitrogen topdressing levels (80, 60, and 40 kg·ha-1) during the tomato growth period in Ningxia, China. The results showed that increasing the aeration ratio in the range of 0-15% was conducive to the enhancement of tomato root vigor (the ability of triphenyltetrazolium chloride to be reduced, 3-104%) and the leaf net photosynthetic rate (14-63%), favorable to the facilitation of plant dry matter accumulation (3-59%) and plant nitrogen accumulation (2-70%), and beneficial to the improvement of tomato yield (12-44%) and fruit quality. Interestingly, since the aeration ratio exceeded 10%, the increase in the aeration ratio showed no significant effects on the single-fruit weight, tomato yield, and fruit quality. Moreover, with aerated underground drip irrigation, properly reducing the traditional nitrogen topdressing level (80 kg·ha-1) by 25% was favorable for enhancing tomato root vigor (5-31%), increasing tomato yield (0.5-9%), and improving fruit soluble solid accumulation (2-5%) and soluble sugar formation (4-9%). Importantly, increasing the aeration ratio by 5% could compensate for the adverse effects of reducing the nitrogen topdressing level by 25% by improving the leaf photosynthetic rate, promoting plant dry matter accumulation, increasing tomato yield, and enhancing the soluble solid and soluble sugar accumulation in tomato fruits. Synthetically considering the decrease in the nitrogen topdressing amount, leading to plant growth promotion, a tomato yield increase, and fruit quality improvement, a favorable nitrogen topdressing level of 60 kg·ha-1 and the corresponding proper aeration ratio of 10% were suggested for tomato underground drip irrigation in the Yinbei Irrigation District of Ningxia.

Nickel molybdate/cobalt iron carbonate hydroxide heterojunction with oxygen vacancy enables interfacial synergism to trigger oxygen evolution reaction.

The development of electrocatalysts with excellent performance toward oxygen evolution reaction (OER) for the production of hydrogen is of great significance to alleviate energy crisis and environmental pollution. Herein, the heterostructure (NMO/FCHC-0.4) was fabricated by the coupling growth of NiMoO4 (NMO) and cobalt iron carbonate hydroxide (FCHC) on nickel foam as an electrocatalyst for OER. The interfacial synergy on NMO/FCHC-0.4 heterojunction can promote the interfacial electron redistribution, affect the center position of d band, optimize the adsorption of intermediate, and improve the conductivity. Beyond, oxygen defect sites are conducive to the adsorption of intermediates, and increase the number of active sites. Real-time OER kinetic simulation revealed that the interfacial synergism and molybdate could reduce the adsorption of hydroxide, promote the deprotonation step of M-OH, and facilitate the formation of M-OOH (M represents the metal active site). As a result, NMO/FCHC-0.4 displays excellent OER electrocatalytic performance with an overpotential of 250/280 mV at the current density 100/200 mA cm-2 and robust stability at 100 mA cm-2 for 100 h. This work provides deep insights into the roles of interfacial electronic modulation and oxygen vacancy to design high-efficiency electrocatalysts for OER.

Electronic modulation and reaction-pathway optimization on three-dimensional seaweed-like NiSe@NiMn LDH heterostructure to trigger effective oxygen evolution reaction.

The development of low-cost and high-efficiency electrocatalysts for the oxygen evolution reaction (OER) is essential to produce high-purity hydrogen in large scale. Herein, a three-dimensional (3D) seaweed-like hierarchical structure was fabricated using two-dimensional (2D) NiMn LDH nanosheets wrapped on one-dimensional (1D) NiSe nanowires with nickel foam (NF) as a substrate (NiSe@NiMn LDH/NF) via hydrothermal and electrodeposition processes. Owing to the strong interfacial synergy, 3D seaweed-like hierarchical structure, higher conductivity, and strong structural stability, the NiSe@NiMn LDH/NF exhibited superior OER performance with an overpotential of 287 mV at 100 mA cm-2, and stably operated for 160 h at large current. Moreover, the overall water splitting system with NiSe@NiMn LDH/NF as the anode and Pt/C/NF as the cathode exhibited a low cell voltage of 1.59/1.64 V to reach 50/100 mA cm-2, and excellent stability for 110 h at 300 mA cm-2. The density function theory (DFT) calculations unveiled that NiSe@NiMn LDH enabled the interfacial synergy, reallocating the electron density at the interface, and further weakening the energy barrier of OH* by strengthening chemical bonds with OH* intermediates to improve the intrinsic OER activity.

Coupling effect and electronic modulation for synergistically enhanced overall alkaline water splitting on bifunctional Fe-doped CoBi/CoP nanoneedle arrays.

Designing bifunctional electrocatalysts with high efficiency and low cost for water splitting is urgently required for the production of green hydrogen. Herein, a bifunctional iron-doped cobalt borate/cobalt phosphide hybrid supported on nickel foam (Fe-CoBi/CoP/NF) was fabricated via hydrothermal and phosphating process. Benefit from the unique nanoneedle architecture for faster mass transfer, the existence of borate on CoBi for accelerating proton transfer, the moderate adsorption of H* species on CoP, Fe doping and the synergistic effect between CoBi and CoP, Fe-CoBi/CoP/NF hybrid exhibits a low overpotential of 137 mV and 260 mV at 100 mA cm-2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Moreover, Fe-CoBi/CoP/NF||Fe-CoBi/CoP/NF also presents a low cell potential of 1.65 V@100 mA cm-2 for overall alkaline water splitting and excellent durability (128 h) without decay. This work provides a new insight into the design of bifunctional electrocatalysts simultaneously through the morphological engineering and heteroatomic doping.

La and S Co-Doping Induced the Synergism of Multiphase Nickel-Iron Nanosheets with Rich Oxygen Vacancies to Trigger Large-Current-Density Oxygen Evolution and Urea Oxidation Reactions.

The development of cost-effective electrocatalysts for oxygen evolution reaction (OER) and urea oxidation reaction (UOR) is of great significance for hydrogen production. Herein, La and S co-doped multiphase electrocatalyst (LSFN-63) is fabricated by metal-corrosion process. FeOOH can reduce the formation energy of NiOOH, and enhance the stability of NiOOH as active sites for OER/UOR. The rich oxygen vacancies can increase the number of active sites, optimize the adsorption of intermediates, and improve electrical conductivity. Beyond, La and S co-doping can also regulate the electronic structure of FeOOH. As a result, LSFN-63 presents a low overpotential of 210/450 mV at 100/1000 mA cm-2 , small Tafel slope (32 mV dec-1 ), and outstanding stability under 1000 mA cm-2 @60 h, and can also display excellent OER activity with 180 mV at 250 mA cm-2 and long-term catalytic durability at 250 mA cm-2 @135 h in 30 wt% KOH under 60 °C. Moreover, LSFN-63 demonstrates remarkable UOR performance in 1 m KOH + 0.5 m urea, which just requires an ultra-small overpotential of 140 mV at 100 mA cm-2 , and maintain long-term durability over 120 h. This work opens up a promising avenue for the development of high-efficiency electrocatalysts by a facile metal-corrosion strategy.

Effect of an individualized digital coaching program on swallowing function in stroke patients.

PURPOSE: Dysphagia is a common complication after a stroke. Home-based rehabilitation would be an alternative or complementary solution to dysphagia management. This study aimed to validate the effect of an individualized digital coaching program on swallowing function in stroke patients. METHODS: A total of 109 patients were enrolled and randomly assigned to either the intervention group (received a 6-week individualized digital coaching program) or the control group (standard care). The primary outcome was a functional oral intake scale (FOIS). The secondary outcomes were the swallowing quality-of-life questionnaire (SWAL-QOL) and pneumonia. RESULTS: Among 101 patients, the number of patients who recovered from dysphagia in the intervention group was significantly more than that of the control group at three weeks. Concurrently, the comparison between the control and intervention groups was non-significant at six weeks. The change in the swallowing quality-of-life questionnaire of the intervention group was significantly more significant than that of the control group. No significant difference in the incidence of pneumonia was observed. CONCLUSION: The individualized digital coaching program can improve swallowing function and swallowing quality-of-life (SWAL-QOL) in stroke patients, indicating its potential for home-based rehabilitation.

Self-sacrificial reconstruction of MoO42- intercalated NiFe LDH/Co2P heterostructures enabling interfacial synergies and oxygen vacancies for triggering oxygen evolution reaction.

Exploring high-efficiency electrocatalysts for oxygen evolution reaction (OER) is one of the most important concerns to produce hydrogen in water electrolysis. Herein, the FNM/Co2P-0.4 heterostructure was designed as an electrocatalyst for the OER process by the combination of MoO42- intercalating NiFe LDH and Co2P on nickel foam (NF). The surface reconstruction and MoO42- leaching can induce the conversion of Co2P and NiFe LDH on FNM/Co2P-0.4 to generate Co/NiOOH with more oxygen vacancies. Beyond, CoOOH and NiOOH can also synergize to reduce the energy barrier of OER, optimize conductivity, and improve stability. The surface reconstruction and the formation of OOH⁎ were further unveiled by in-situ UV-vis absorption spectra and Fourier-transformed alternative current voltammetry (FTACV). The integration of interfacial synergies and oxygen vacancies can facilitate the adsorption/desorption of intermediates, regulate the d-band center, and expose more active sites. And as a result, FNM/Co2P-0.4 shows a significant low overpotential (240 mV) at 50 mA cm-2, a small Tafel (74 mV dec-1), low activation energy (Ea) and remarkable durability. This work provides a new pathway to improve the OER performance by using interfacial synergies and rich oxygen vacancies derived from the self-sacrificial reconstruction of heterostructured electrocatalysts.

Doping Mo into NiFe LDH/NiSe Heterostructure to Enhance Oxygen Evolution Activity by Synergistically Facilitating Electronic Modulation and Surface Reconstruction.

It is of great significance to design highly efficient electrocatalysts with abundant earth elements instead of precious metals for water splitting. Herein, Mo-doped NiFe-layered double hydroxides/NiSe heterostructure (Mo-NiFe LDH/NiSe) was fabricated by coupling Mo-doped NiFe LDH and NiSe on nickel foam (NF). The heterostructure electrocatalyst showed ultra-low overpotential (250 mV) and remarkable durability for oxygen evolution reaction (OER) at 150 mA cm-2 . Both theoretical and experimental results confirmed that Mo doping and interfacial synergism induced the interfacial charge redistribution and the lifted d-band center to weaken the energy barrier (EB) of the formation of OOH* . Mo doping also facilitated the surface reconstruction of NiFe LDH into Ni(Fe)OOH as the active sites under electro-oxidation process. This work provides a facile strategy for electronic modulation and surface reconstruction of OER electrocatalyst by transition metal doping and heterostructure generation.

Synergistic coupling of heterostructured porous CoP nanosheets with P doped NiO for highly efficient overall alkaline water splitting.

Exploring non-noble metal materials as bifunctional catalysts for water electrolysis is of great significance for the development and utilization of hydrogen energy. Herein, a flower branch-leaf shaped phosphide/oxide heterogeneous electrocatalyst located on Ni foam (CoP/P-NiO/NF) was developed through hydrothermal and phosphorization strategy. Benefiting from the strong ability to dissociate H2O molecules on P-NiO and the suitable adsorption of intermediate H species on CoP, the optimal CoP/P-NiO/NF exhibited outstanding performance with low overpotentials of 52 mV at current density of 10 mA cm-2, smaller Tafel slopes of 73.6 mV dec-1 for hydrogen evolution reaction (HER). Meanwhile, CoP/P-NiO/NF indicated 265 mV at 100 mA cm-2 with Tafel slope of 101.8 mV dec-1 for oxygen evolution reaction (OER) due to the optimal redistribution of electrons among Ni2+, Co2+ and Co3+ for favorable adsorption/desorption of oxygen-intermediates. Both HER and OER shown robust stability during 32 h without decline. The corresponding two-electrode system for overall alkaline water splitting required a low voltage of 1.6 V at 100 mA cm-2 with long stability (20 h) which is far lower than that on RuO2-Pt/C and many other reported non-noble metal electrocatalysts. This work demonstrates that the synergistic effect and morphology engineering play vital roles in the enhanced electrocatalytic performance.

Hierarchical sheet-on-sheet heterojunction array of a ß-Ni(OH)2/Fe(OH)3 self-supporting anode for effective overall alkaline water splitting.

Rationally designing high-performance non-noble metal electrocatalysts is of essence to improve energy conversion efficiency in water splitting. Herein, a unique 3D hierarchical sheet-on-sheet heterojunction between Fe(OH)3 and ß-Ni(OH)2 on pretreated Ni foam (NiFe-HD/pre-NF) was fabricated by a two-step strategy involving the interfacial hydrolysis-deposition of Fe2+ and electrodeposition of Ni2+. The presence of the Ni-O-Fe bridge at the Fe(OH)3/ß-Ni(OH)2 heterointerface can induce interfacial electronic redistribution to form Ni3+ in NiFe-HD/pre-NF, and further strengthen the adsorption of OH- and weaken the O-H bond to change the rate-determining step (RDS) for accelerating OER kinetics. Benefiting from the sheet-on-sheet architecture and dual-phase synergism on NiFe-HD/pre-NF, the optimal NiFe-HD/pre-NF exhibits excellent OER performance with a lower overpotential of 256 mV at 100 mA cm-2, a small Tafel slope of 81 mV dec-1, high intrinsic activity and robust stability. Alkaline water-splitting using NiFe-HD/pre-NF as the anode requires ultralow cell voltages of 1.62 V and 1.83 V at current densities of 100 mA cm-2 and 400 mA cm-2, respectively, which are comparable with commercial alkaline water electrolysis, and operates steadily at a current density of 100 mA cm-2 for 85 h without decay. This work proposes a facile strategy for constructing heterojunctions and modulating electronic interaction to develop electrocatalysts with new architectures.

Electronic modulation and proton transfer by iron and borate co-doping for synergistically triggering the oxygen evolution reaction on a hollow NiO bipyramidal prism.

Designing an Earth-abundant and inexpensive electrocatalyst to drive the oxygen evolution reaction (OER) for high-purity hydrogen production is of great importance. Herein, the cation (iron) and anion (borate) co-doping strategy was proposed to effectively trigger the OER performance on a low-cost NiO material. The optimal hollow Fe/Bi-NiO bipyramidal prism shows superior OER performance, and displays a low overpotential (261 mV) at 10 mA cm-2, accompanied by a low Tafel slope (46 mV dec-1), excellent intrinsic activity and robust stability. The overall alkaline water splitting using Fe/Bi-NiO/NF as an anode affords low cell voltages of 1.50 and 1.63 V at 10 and 100 mA cm-2, and operates steadily at a high current density of 100 mA cm-2 for 55 h without decay. The excellent electrocatalytic activity could be ascribed to the hollow structure to shorten the mass transfer pathway, the electronic modulation by Fe doping, the increased accessible electroactive sites created by oxygen vacancies through borate doping, and the formation of BO33--OH- to accelerate the deprotonation of OHads.

How does hybrid environmental governance work? Examining water rights trading in China (2000-2019).

Intensifying competition for water induces the growth of water markets in several countries for sharing water between rural communities and cities. While there is a growing recognition that adoption of market mechanisms in environmental governance relies on the state and different institutional arrangements, much less is known about how the interconnections among the state, market-tools, and the community work in practice. In China's distinctive political system, the central government has adopted a 'Two-Hands' approach () to water governance - a combination of strong central regulation and infrastructure development on the one hand, and adoption of market principles on the other to improve water reallocation. A recent study has explored the policy evolution underpinning this transition. However, no studies have systematically examined the implementation of the Two-Hands approach to reveal the underlying institutional hybrid patterns in environmental governance. This study fills this research gap by employing a Fuzzy Set Qualitative Comparative Analysis (fsQCA) to analyze how the interplay of the central government, market, and local governance shapes water rights trading patterns. A total of 29 water-scarce cities using water rights trading with 385 transactions were investigated for the period between 2000 and 2019 by combining evidence from fsQCA and qualitative case-studies. The implications drawn from interpreting the results are as follows: (1) the central government shapes the development of the market and its transactions but this is expressed in multiple ways through pilot projects and the national water exchange platform; (2) establishing water markets and investing in water infrastructure are mutually reinforcing, rather than mutually exclusive; and (3) local governments employ different property rights arrangements to adapt water markets in China's centralized politically institutional context.

Analysis of the application of echocardiography technology in diagnosis of acute myocardial infection.

The purpose of this study is to enhance the diagnosis and treatment of acute myocardial infarction, prolong the life of patients with coronary heart disease, and improve the survival rate. In this study, 30 healthy adults are classified as the control group, and real-time three-dimensional echocardiography technology is used to observe the myocardial changes and characteristics of right ventricular morphology after acute myocardial infarction, which provides a theoretical basis for early clinical diagnosis and early intervention. The results show that the real-time three-dimensional echocardiography can provide more diagnostic information through the three-dimensional imaging of the cardiac structure and the real-time observation of the cardiac structures and their adjacent relations from any angle by combining the cutting and rotation of the image. Conventional examination methods such as two-dimensional echocardiography have a narrow time window for the detection of transient myocardial ischemia, which can clearly diagnose the ischemia in early stage, but its diagnostic ability in the late stage of ischemia is limited. When obtaining the cardiac full volume image within one cardiac cycle, echocardiography can quickly acquire dynamic images of ventricular volume without splicing and combine with the function of automatic delineation of endocardium of the 3d workstation to construct a real ventricular stereo image independent of the assumptions of the geometric model, so as to solve the inconvenience of the complex right ventricular space configuration and the obvious difference of its shape with the different load state. Therefore, as a new non-invasive imaging technique, it has unique advantages in accurate measurement of heart volume and evaluation of heart function.

Surface sites assembled-strategy on Pt-Ru nanowires for accelerated methanol oxidation.

Modifying the surface active sites of Pt-based catalysts at the atomic level is of great significance to enhance the electrooxidation of methanol molecules. Herein, efficient active site assembly strategies are proposed, precisely, aimed at building high-performance electrocatalysts. Serving as proof-of-concept examples, both instances of Pt nanowires surface doping isolated Ru atoms (Ru/Pt NWs) and Ru nanoparticles supported on Pt nanowires (Ru@Pt NWs) are specially designed to optimize the catalytic performance of methanol oxidation reaction (MOR). The specific activity and mass activity of optimal Ru/Pt NWs can reach up to 3.93 mA cm-2 and 568.40 mA mg-1Pt, respectively, which is 1.53/1.94 times that of the Ru@Pt NWs and 2.03/2.59 times that of pure Pt NWs. Detailed studies on mechanism reveal that the Pt-Ru alloy can significantly improve the electron transfer kinetics of MOR, and activate more Pt atoms involved in the Langmuir-Hinshelwood (L-H) pathway compared with Ru@Pt NWs, all of which collectively accelerate the methanol oxidation. This surface engineering strategy via assembling active sites can reveal a promising method in the design of advanced Pt-based catalysts for direct methanol fuel cells.

Interfacial synergy between dispersed Ru sub-nanoclusters and porous NiFe layered double hydroxide on accelerated overall water splitting by intermediate modulation.

Construction of an efficient bifunctional electrocatalyst through a rational interface-engineering strategy to optimize the adsorption energy of H* and OH* species at the atomic/molecular level is of great importance for water splitting. Although conventional NiFe layered double hydroxide (LDH) shows excellent performance for alkaline oxygen evolution reactions (OERs), it shows extremely poor activity toward hydrogen evolution reactions (HERs) due to weak hydrogen adsorption and sluggish kinetics. In this work, integration of sub-nanoscale Ru species with NiFe LDH can dramatically enhance the adsorption energy of H* and improve their HER kinetics. Besides, benefitting from the desired potential-induced strategy, the Ru-NiFe LDH interfaces will convert to RuO2-NiFe(OOH)x interfaces to optimize the adsorption energy of OH* to meet the requirement of strengthening the OER performance. Strikingly, the Ru-NiFe LDH-F/NF sample (NF: Ni foam) shows an excellent OER and HER performance with an overpotential of 230.0 mV and 115.6 mV at a current density of 10 mA cm-2, respectively, as well as outstanding durability. The overall water splitting device was fabricated by using Ru/NiFe LDH-F/NF as both the HER and OER electrode with a potential of 1.53 V to achieve a current density of 10 mA cm-2. In addition, the theoretical calculations demonstrated that the Ru-NiFe LDH interfaces could optimize the adsorption energy of H* and OH*. This study provides a new insight into the development of highly efficient bifunctional electrocatalysts for water electrolysis.

2D Fe-doped NiO nanosheets with grain boundary defects for the advanced oxygen evolution reaction.

Two-dimensional (2D) nanomaterials with grain boundary defects are attractive to researchers in many fields, such as energy conversion and storage, sensing, catalysis and biological medicine. In this work, a nanostructure of 2D Fe-doped NiO nanosheets (NiFexO) with grain boundary defects was designed and applied in the electrocatalytic oxygen evolution reaction. This nanomaterial was synthesized through a solvothermal strategy followed by a thermally driven conversion process. In general, NiFexO electrocatalysts were fabricated with gradual morphological variation depending on the atomic ratio of Ni : Fe. It is surprising that the Fe content determines the electrocatalytic performance and the overpotential of water oxidation exhibits an inverted volcanic pattern. As expected, the as-prepared 2D NiFe0.1O nanosheets with grain boundary defects exhibit enhanced OER activity (274 mV@10 mA cm-2) compared with the oxide electrocatalyst reported in 1.0 M KOH owing to the advantages of abundant active sites. This work will shed light on the design and fabrication of novel-structured nanocatalysts.

In situ fabrication of dynamic self-optimizing Ni3S2 nanosheets as an efficient catalyst for the oxygen evolution reaction.

In this work, a dynamic self-optimizing material consisting of nickel-sulfide nanosheets anchored onto Ni foam (DSO-Ni3S2-NF) as the model material was constructed using a hydrothermal method, and its electrocatalytic performance for oxygen evolution was evaluated. It was found that the electrocatalytic activity of the dynamic self-optimizing (DSO) 25 h-Ni3S2-NF for oxygen evolution is significantly enhanced compared with that of pristine 0 h-Ni3S2-NF since the formed oxide layer evolves into new active sites and the specific process of activity optimization was explored dynamically. The best oxygen evolution reaction (OER) performance was achieved by 25 h-Ni3S2-NF catalyst, which required merely 241 mV overpotential to deliver a current density of 20 mA cm-2, and its Tafel slope was as low as ∼40 mV dec-1, which was superior to most nickel-based catalysts, in 1 M KOH electrolyte. The current density was found to be increased gradually at the same potential and the stability test curves were steady with ignorable decline, showing that the promising strategy of the preparation of a dynamic self-optimizing pre-catalyst may open a new pathway to prepare low-cost, high-performance and stable water splitting catalysts.

An Interfacial Electron Transfer on Tetrahedral NiS2 /NiSe2 Heterocages with Dual-Phase Synergy for Efficiently Triggering the Oxygen Evolution Reaction.

Tetrahedral NiS2 /NiSe2 heterocages with rich-phase boundaries are synthesized through a simultaneous sulfuration/selenylation process using Ni-based acetate hydroxide prisms as precursor. Such a nanocage-like NiS2 /NiSe2 heterostructure can expose more active sites, accelerate the mass transport of the ions/gas, and optimize the interfacial electronic structure, which shows a significantly lower overpotential of 290 mV at 20 mA cm-2 than those of NiS/NiS2 and NiSe2 as counterparts. The experimental characterizations and theoretical density functional theory (DFT) calculations unveil that the interfacial electron transfer from NiSe2 to NiS2 at the heterointerface can modulate the electronic structure of NiS2 /NiSe2 , which further cooperates synergistically to change the Gibbs free energy of oxygen-containing intermediates as the rate-determining step (RDS) from 2.16 eV (NiSe2 ) and 2.10 eV (NiS2 ) to 1.86 eV (NiS2 /NiSe2 heterostructures) during the oxygen evolution reaction (OER) process. And as a result, tetrahedral NiS2 /NiSe2 heterocages with dual-phase synergy efficiently trigger the OER process, and accelerate the OER kinetics. This work provides insights into the roles of the interfacial electron transfer in electrocatalysis, and can be an admirable strategy to modulate the electronic structure for developing highly active electrocatalysts.

Alkaline-Etched NiMgAl Trimetallic Oxide-Supported KMoS-Based Catalysts for Boosting Higher Alcohol Selectivity in CO Hydrogenation.

The acidity/alkalinity and structural properties of NiMgAl trimetallic oxides (MMOs) can be effectively modulated by the alkaline-etching process with various etching times, which are further used as a support to prepare KMoS-based catalysts through the cetyltrimethylammonium bromide-encapsulated Mo-precursor strategy. The enriched surface anion groups in alkaline-etched MMO affect the textural properties, metal-support interaction, and sulfidation degree of the as-synthesized KMoS-based catalysts. As a result, KMoS-based catalysts using alkaline-etched MMO as supports effectively enhance the reducibility and dispersion of Mo species, which exert a positive influence on higher alcohol synthesis (HAS) performance in CO hydrogenation. A proper balance between acidity/alkalinity and structural properties in K, Mo/MMO- x catalysts can significantly enhance the alcohol selectivity in HAS from 55 to 65% (carbon selectivity). The formation of C2+ alcohols can be boosted by adol condensation with optimal acidic/basic properties via suppressing the acidity and increasing the amount of basic sites. The alkaline-etching process also significantly improves the space time yield of C2+ alcohols over unit mass of molybdenum.

The in situ etching assisted synthesis of Pt-Fe-Mn ternary alloys with high-index facets as efficient catalysts for electro-oxidation reactions.

Pt-Based alloys enclosed with high-index facets (HIFs) generally show much higher specific catalytic activities than their counterparts with low-index facets in electro-catalytic reactions. However, the exposure of a certain Pt surface would require a well-defined nanostructure, which usually can only be obtained at larger sizes. Therefore, a low dispersion of Pt atoms in Pt-based alloys with HIFs would affect the atomic utilization of Pt, resulting in most of these Pt-based alloys exhibiting lower mass activity than commercial Pt/C and Pt black catalysts for electro-catalytic reactions. Herein, we address a novel strategy to divide the surface areas of larger sized nanocrystals into small surface area nanocrystals by in situ etching Pt-Fe-Mn concave cubes (CNCs) while maintaining the morphology of the Pt-Fe-Mn alloys to improve the utilization of Pt atoms and thus increase the mass activity. Remarkably, the Pt-Fe-Mn unique concave cube (UCNC) nanocrystals (NCs) showed much higher specific and mass activities toward the methanol oxidation reaction (MOR) than the Pt-Fe-Mn CNCs, commercial Pt black and Pt/C. The kinetic analysis from Tafel plots indicated that UCNC Pt-Fe-Mn NCs had the lowest Tafel slope at whole potentials and the splitting of the first C-H bond of a CH3OH molecule with the first electron transfer was the rate-determining step at high potentials (above 0.45 V). In situ Fourier transform infrared reflection (FTIR) spectroscopic investigation at the molecular level indicated that methanol chemical absorption took place at a low potential of -0.2 V at the UCNC NC electrode. Meanwhile, much higher CO2 productivity was observed at the UCNC NC electrode, indicating the strong anti-poisoning ability of the UCNC Pt-Fe-Mn NCs during methanol electrooxidation. Furthermore, in the formic acid oxidation (FAOR) test, the activity and long-term durability of the Pt-Fe-Mn UCNC NCs were also found to be superior to those of the Pt-Fe-Mn CNCs, commercial Pt black and Pt/C. The enhanced catalytic performance in both the MOR and FAOR is most probably due to the unique HIF structure consisting of small sized particles, enhanced Pt utilization, the richness of crystalline defects and synergetic effects of Pt, Fe, and Mn metals. Our present work provides an insight into the rational design of Pt based alloys with HIFs to improve the catalytic performance of electro-catalytic reactions for fundamental study.