Ligand-Induced Electronic Structure Modulation of Self-Evolved Ni3S2 Nanosheets for the Electrocatalytic Oxygen Evolution Reaction.

Modulating the electronic structure of the electrocatalyst plays a vital role in boosting the electrocatalytic performance of the oxygen evolution reaction (OER). In this work, we introduced a one-step solvothermal method to fabricate 1,1-ferrocene dicarboxylic acid (FcDA)-decorated self-evolved nickel sulfide (Ni3S2) nanosheet arrays on a nickel foam (NF) framework (denoted as FcDA-Ni3S2/NF). Benefiting from the interconnected ultrathin nanosheet architecture, ligand dopants induced and facilitated in situ structural reconstruction, and the FcDA-decorated Ni3S2 (FcDA-Ni3S2/NF) outperformed its singly doped and undoped counterparts in terms of OER activity. The optimized FcDA-Ni3S2/NF self-supported electrode presents a remarkably low overpotential of 268 mV to achieve a current density of 10 mA cm-2 for the OER and demonstrates robust electrochemical stability for 48 h in a 1.0 M KOH electrolyte. More importantly, in situ electrochemical Raman spectroscopy reveals the generation of catalytically active oxyhydroxide species (NiOOH) derived from the surface construction during the OER of pristine FcDA-Ni3S2/NF, contributing significantly to its superior electrocatalytic performance. This study concerns the modulation of electronic structure through ligand engineering and may provide profound insight into the design of cost-efficient OER electrocatalysts.

Improving the Sulfurophobicity of the NiS-Doping CoS Electrocatalyst Boosts the Low-Energy-Consumption Sulfide Oxidation Reaction Process.

Producing sulfur from a sulfide oxidation reaction (SOR)-based technique using sulfide aqueous solution has attracted considerable attention due to its ecofriendliness. This study demonstrates that NiS-doped cobalt sulfide NiS-CoS-supported NiCo alloy foam can deliver the SOR with superior electrocatalytic activity and robust stability compared to reported non-noble metal-based catalysts. Only 0.34 V vs RHE is required to drive a current density of 100 mA cm-2 for the SOR. According to the experiment, the catalyst exhibits a unique sulfurophobicity feature because of the weak interaction between sulfur and the transition metal sulfide (low affinity for elemental sulfur), preventing electrode corrosion during the SOR process. More impressively, the chain-growth mechanism of the SOR from short- to long-chain polysulfides was revealed by combining electrochemical and spectroscopic in situ methods, such as in situ ultraviolet-visible and Raman. It is also demonstrated that electrons can transfer straight from the sulfion (S2-) to the active site on the anode surface during the low-energy-consumption SOR process. This work provides new insight into simultaneous energy-saving hydrogen production and high-value-added S recovery from sulfide-containing wastewater.

Divalent Oxidation State Ni as an Active Intermediate in Prussian Blue Analogues for Electrocatalytic Urea Oxidation.

Urea degradation is one of the most crucial links in the natural nitrogen cycle. Exploring the real active species in the urea electro-oxidation process is of great significance for understanding the urea electro-oxidation mechanism and designing catalysts. A highly active and stable Prussian blue analogue catalyst (PBA@NiFe/NF) loaded on nickel foam was synthesized for electro-oxidation of urea. In situ Raman spectra revealed that Ni in PBA@NiFe/NF was able to maintain a stable divalent nickel (Ni(II)) state for up to 3.5 h during the initial urea oxidation process, which is rarely reported in previous research studies. In addition, with the participation of iron, the Ni-Fe bimetallic center significantly improves the electro-oxidation of urea. Our work provides a new idea for prolonging the Ni(II) activity in electrocatalytic oxidation of urea.

Urea-oxidation-assisted electrochemical water splitting for hydrogen production on a bifunctional heterostructure transition metal phosphides combining metal-organic frameworks.

Electrocatalyzed urea-assisted wastewater splitting is a promising approach for sustainable hydrogen production. However, the lack of cost-efficient electrocatalysts hinders its practical application. Herein, bimetal phosphide (NiCoPx) nanowire arrays decorated with ultrathin NiFeCo metal-organic framework (NiFeCo-MOF) nanosheets on porous nickel foam (NF) were designed for urea-assisted wastewater splitting. The core-shell NiCoPx@NiFeCo-MOF hybrids were prepared via successive hydrothermal, gas-phase phosphorization and hydrothermal strategies. Encouragingly, the novel NiCoPx@NiFeCo-MOF/NF electrode served as an excellent bifunctional electrocatalyst for both the cathodic hydrogen evolution reaction (HER) and the anodic urea oxidation reaction (UOR) in urea-assisted water splitting, which merely required an overpotential of 44 mV to deliver a current density of 10 mA cm-2 for HER and a voltage of 1.37 V to deliver a current density of 100 mA cm-2 for UOR in 1.0 M KOH + 0.5 M urea. Benefiting from the highly exposed electroactive sites in exquisite three-dimensional (3D) hierarchical structure, multicomponent synergistic effect, accelerated electron transfer, easy electrolyte access and diffusion of released gas bubbles, the as-fabricated NiCoPx@NiFeCo-MOF/NF exhibited outstanding electrocatalytic performance. The mechanism of water splitting was elucidated by density functional theory calculations. Interestingly, NiFeCo-MOF possessed optimized COO* adsorption ability on Ni sites that were beneficial to UOR intermediates. More significantly, this work paves the way for the design and fabrication of bifunctional electrocatalysts for urea-containing wastewater treatment and sustainable hydrogen production.

The Influence of Family Supportive Supervisor Behavior on Employee Creativity: The Mediating Roles of Psychological Capital and Positive Emotion.

In an increasingly complex external environment, innovation is an important way for companies to build sustainable competitiveness. This research discusses employee creativity from the perspective of Family Supportive Supervisor Behavior (FSSB) based on conservation of resource theory, social exchange theory, psychological capital theory and emotional spillover theory. Through a series of surveys of employees in different companies and jobs, we can understand the impact of family-supporting supervisors' behavior on their creativity. Combined with the survey data, a structural equation model (SEM) is constructed to analyze the mediating effects of psychological capital and positive emotions based on the causal mediation model. The research found that the positive influence of family-supporting supervisors' behavior on employees' creativity has three forms. First, supervisors improve employees' motivation and sense of efficacy by providing various support resources. Second, supervisors can generate positive spillover effects among employees by influencing employees' psychological state. Third, supervisors stimulate the creativity of subordinates by promoting work participation and mobility. According to the research conclusions, in order to improve the employee creativity, we should provide incentives to encourage supervisors to carry out family support behaviors, identify employee characteristics to help supervisors provide personalized support, cultivate family supportive leaders, and attach importance to emotional support and play the role of psychological capital and positive emotions.

Electro-Oxidation of Glycerol to High-Value-Added C1-C3 Products by Iron-Substituted Spinel Zinc Cobalt Oxides.

Glycerol is a byproduct of biodiesel production and can be a low-cost source for some high-value C1-C3 chemicals. The conversion can be achieved by photo-, thermo-, and electro-catalysis methods. The electrocatalytic oxidation method is attractive due to its moderate reaction conditions and high electron to product efficiency. Most reported catalysts are based on noble metals, while metal oxides are rarely reported. Here, we investigated the electro-oxidation of glycerol on a series of ZnFexCo2-xO4 (x = 0, 0.4, 1.0, 1.4, and 2.0) spinel oxides. Seven types of value-added C1-C3 products including formate, glycolate, lactate, and glycerate can be obtained by this approach. The selectivity and Faraday efficiency toward these products can be tuned by adjusting the Fe/Co ratio and other experimental parameters, such as the applied potential, glycerol concentration, and electrolyte pH.

Self-supported MoO2-MoO3/Ni2P hybrids as a bifunctional electrocatalyst for energy-saving hydrogen generation via urea-water electrolysis.

The electronic modulation and morphology control of electrocatalysts are effective strategies to improve their catalytic performance. Herein, MoO2-MoO3/Ni2P nanoflowers were fabricated on the skeleton of conductive nickel foam as an electrocatalyst with enhanced performance via a universal hydrothermal and phosphating method. The introduction of P and Mo into the nickel-based catalyst through the co-doping strategy effectively adjusted the electronic structure of the Ni active sites, thereby significantly improving the performance of the catalyst. Particularly, the introduction of Mo allowed adjusting the morphology of the material, thereby increasing the electrochemical active area and promoting the exposure of more active sites. This strategy for improving the electrocatalyst's performance in urea-assisted water splitting will provide a new concept for the simultaneous mitigation of the energy crisis and environmental contamination.

Advances in hydrogen production from electrocatalytic seawater splitting.

As one of the most abundant resources on the Earth, seawater is not only a promising electrolyte for industrial hydrogen production through electrolysis, but also of great significance for the refining of edible salt. Despite the great potential for large-scale hydrogen production, the implementation of water electrolysis requires efficient and stable electrocatalysts that can maintain high activity for water splitting without chloride corrosion. Recent years have witnessed great achievements in the development of highly efficient electrocatalysts toward seawater splitting. Starting from the historical background to the most recent achievements, this review will provide insights into the current state, challenges, and future perspectives of hydrogen production through seawater electrolysis. In particular, the mechanisms of overall water splitting, key features of seawater electrolysis, noble-metal-free electrocatalysts for seawater electrolysis and the underlying mechanisms are also highlighted to provide guidance for fabricating more efficient electrocatalysts toward seawater splitting.

Dual mode electrochemical-photoelectrochemical sensing platform for hydrogen sulfide detection based on the inhibition effect of titanium dioxide/bismuth tungstate/silver heterojunction.

A novel dual mode sensing platform is constructed for highly selective detection of H2S, attributing to the efficient electrochemical (EC) and photoelectrochemical (PEC) signal responses of the TiO2/Bi2WO6/Ag heterojunction. On the one hand, TiO2/Bi2WO6/Ag heterojunction with excellent catalytic performance for the reduction of H2O2 could be employed act as a probe, providing a remarkable EC response through an amperometric i-t method. On the other hand, this hybrid provides a photoelectric beacon with a favorable energy-band configuration. More interestingly, the EC and PEC responses of the functionalized electrodes are proportionately decreased in response to the generation of Bi2S3 and Ag2S nanoparticles upon exposure to sulfide ions. The decreased EC and PEC signals could be ascribed to the poor catalytic properties and the recombination of photoexcited electron - hole pairs of the Bi2S3 and Ag2S. Under the optimal conditions, the dual mode sensor exhibits a wide linear response in the range from 0.5 µM to 300 µM with a detection limit of 0.08 µM for the detection of H2S. Enabled by this unique sensitization mechanism, the proposed sensing platform displays an excellent analytical performance with good selectivity, reproducibility and stability, which providing an alternative pathway of H2S detecting in practical application.

Multi-dimensional collaboration promotes the catalytic performance of 1D MoO3 nanorods decorated with 2D NiS nanosheets for efficient water splitting.

The ability to manipulate heterostructures is of great importance to achieve high-performance electrocatalysts for direct water-splitting devices with excellent activity toward hydrogen production. Herein, a novel top-down strategy involving the in situ transformation of one-dimensional MoO3 nanorod arrays grafted with two-dimensional NiS nanosheets supported on a three-dimensional nickel foam skeleton is proposed. Namely, a heterostructured electrocatalyst on the Ni foam skeleton containing MoO3 nanorod arrays decorated with NiS nanosheets is synthesized by a facile hydrothermal method followed by one-step sulfidation treatment. Experimental analysis confirmed that this novel composite has the merits of a large quantity of accessible active sites, unique distribution of three different spatial dimensions, accelerated mass/electron transfer, and the synergistic effect of its components, resulting in impressive electrocatalytic properties toward the hydrogen evolution reaction and oxygen evolution reaction. Furthermore, an advanced water-splitting electrolyzer was assembled with NiS/MoO3/NF as both the anodic and cathodic working electrode. This device requires a low cell voltage of 1.56 V to afford a water-splitting current density of 10 mA·cm-2 in basic electrolyte, outperforming previously reported electrocatalysts and even state-of-the-art electrocatalysts. More significantly, this work provides a way to revolutionize the design of heterostructured electrocatalysts for the large-scale commercial production of hydrogen using direct water-splitting devices.

Hollow V-Doped CoMx (M = P, S, O) Nanoboxes as Efficient OER Electrocatalysts for Overall Water Splitting.

Hollow nanostructures with intricate interior and catalytic effects have been the focus of researchers in energy conversion and storage. Although tremendous efforts have been made, the fabrication of well-defined hollow nanostructures has been rarely reported due to the limitations of the synthetic methods. Herein, we have proposed a general synthetic strategy for the construction of V-doped CoMx (M = P, S, O) nanoboxes (NBs), where the doped V effectively modifies the electronic structure of CoMx to provide a favorable surface electrochemical environment for the adsorption of reaction intermediates (*O, *OH, and *OOH), leading to a significant enhancement in electrocatalytic performance. More importantly, the hollow nanostructures can expose abundant surface active areas and promote the chemical adsorption of reactants and intermediates, greatly contributing to the promotion of electrocatalytic performance. Impressively, the optimal V-doped CoS2 NBs show excellent electrocatalytic oxygen evolution reaction (OER) performance with an overpotential of only 290 mV at 10 mA cm-2, along with outstanding overall water-splitting performance. This work supplies pivotal insights for constructing high-performance OER catalysts on the basis of electronic and geometric engineering.

3D ZnIn2S4 nanosheets decorated ZnCdS dodecahedral cages as multifunctional signal amplification matrix combined with electroactive/photoactive materials for dual mode electrochemical - photoelectrochemical detection of bovine hemoglobin.

The construction of dual mode sensor has gained tremendous attention due to its high accuracy and sensitivity compared with a single-response system. Herein, a novel dual mode sensing platform based on a 3-dimensional (3D) ZnCdS/ZnIn2S4 double-shelled dodecahedral cages (DSDCs) is fabricated as the electrochemical (EC) - photoelectrochemical (PEC) multifunctional signal amplification matrix for the highly selective detection of bovine hemoglobin (BHb). To achieve simple and fast detection of BHb, Au@Cu2O and SnO2/SnS2 are acted as EC - PEC signal indicators, respectively. More interestingly, the electroactive Au@Cu2O and photoactive SnO2/SnS2 are assembled on the 3D ZnCdS/ZnIn2S4 DSDCs, which could effectively increase the electron transfer process, consequently amplifying the readout of the dual mode responses. Besides, polydopamine (PDA) is used as a monomer for protein imprinting. Under the optimized conditions, the dual mode sensor exhibits a wide linear concentration range from 10-19 mg mL-1 to 10-1 mg mL-1 with a low detection limit 6.5 × 10-20 mg mL-1. Furthermore, the excellent selectivity, stability and acceptable reproducibility of the designed sensor will offer an alternation for the detection of other biomacromolecules in clinic diagnosis field.

Ir-Doped Pd Nanosheet Assemblies as Bifunctional Electrocatalysts for Advanced Hydrogen Evolution Reaction and Liquid Fuel Electrocatalysis.

Although great progress in pursuing high-performance catalysts for advanced electrocatalysis has been made, the design of high-efficiency electrocatalysts continues to be a huge challenge for commercializing electrochemical energy technologies. Herein, a three-dimensional (3D) hierarchical assembly nanostructure consisting of ultrathin Ir-doped Pd nanosheets has been well designed, which could serve as a bifunctional electrocatalyst for advanced hydrogen evolution reaction (HER) and liquid fuel electrooxidation. In particular, the optimized Pd83.5Ir16.5 nanocatalyst displays excellent electrocatalytic HER performance with an overpotential of only 73 mV at 10 mA cm-2 along with excellent stability. More importantly, it can also show outstanding electrocatalytic performance for liquid fuel oxidation with a mass activity of 4326.1 mA mgmetal-1 for ethylene glycol oxidation reaction. Mechanistic study reveals that the highly porous 3D nanostructure, the modulation of electronic structure after the introduction of Ir, not only guarantees a high level of exposure of surface active sites and smooth charge transfer but also generates the new active centers for facilitating the adsorption of H2O and recombination of H*, thereby dramatically increasing the intrinsic activity of electrocatalysis.

General synthesis of Pd-pm (pm = Ga, In, Sn, Pb, Bi) alloy nanosheet assemblies for advanced electrocatalysis.

Owing to the synergistic compositional and structural advantages, ultrathin bimetallic nanosheet assembly nanostructures are widely recognized as advanced catalysts for alcohol electrooxidation reaction. Although numerous efforts have been made, the fabrication of well-defined ultrathin bimetallic nanosheet assemblies (NSAs) at large scale is still a tough challenge. Herein, a universal synthetic approach has been proposed to produce a series of well-defined Pd-pm (pm = Ga, In, Sn, Pb, Bi) alloy NSAs. Due to multiple merits of their unique 3D flower-like nanostructure and alloyed crystalline features, the self-supported Pd-pm NSAs show excellent electrocatalytic performance for the methanol oxidation reaction (MOR) and glycerol oxidation reaction (GOR). Given the eco-friendly synthetic concept, facile universality, and outstanding electrocatalytic properties of the generated bimetallic Pd-pm NSAs, we believe that this method could be employed for building more advanced nanocatalysts toward efficient electrocatalytic applications.

Nanoscale engineering of porous Fe-doped Pd nanosheet assemblies for efficient methanol and ethanol electrocatalyses.

Although great successes have been accomplished on the controlled synthesis of 2D and 3D Pd-containing nanomaterials, tapping into the novel Pd-containing electrocatalysts that combined the advantages of both 2D and 3D structures remains a significant challenge. Here, an approach to systematically produce porous Fe-doped Pd nanosheet assemblies (NSAs) with a geometry tuning from PdFe hollow nanospheres (HNSs), PdFe nanocages (NCs), to PdFe nanoplates (NPs) is reported. The inherent ultrathin and porous features endow these PdFe catalysts with excellent electrocatalytic performance. As a result, the optimized 3D PdFe NCs show a much-improved methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) activities in comparison with PdFe HNSs, Pd NPs, and commercial Pd/C catalysts. Moreover, these PdFe nanocatalysts also display greatly enhanced electrocatalytic stability, which can endure 500 cycles with negligible activity loss and structural changes. The mechanism investigations reveal that the introduced Fe atom efficiently modulates the electronic structure of Pd, leading to the downshift of the d-band center of Pd, which is beneficial for the adsorption of reactants. Moreover, the porous nanosheet assembly structure can provide rich mass and electron transfer channels, further boosting the improvement of electrocatalytic performance.

From bimetallic PdCu nanowires to ternary PdCu-SnO2 nanowires: Interface control for efficient ethanol electrooxidation.

At present, although a large number of palladium-based nanowire electrocatalysts have been prepared, there are few reports on nanowires containing rich metal oxides. Herein, porous PdCu alloy nanowires and PdCu-SnO2 nanowires were prepared by using a galvanic displacement synthesis method. Due to their one-dimensional structure, rough surfaces with non-homogeneous edges, electronic effect, and the advanced PdCu/SnO2 interface of the as-synthesized PdCu-SnO2 nanowire catalysts, they exhibited a mass activity of 7770.0 mA mg-1 towards ethanol oxidation, which was 7.6-fold higher than that of Pd/C catalysts (1025.0 mA mg-1). In addition, they behaved strong durability upon chronoamperometry and continuous cyclic voltammetry tests. The electrochemical measurements demonstrated that SnO2 was introduced into the PdCu/SnO2 interface, which promoted the oxidation of ethanol at a lower potential and accelerated the oxidation of Pd-COads via SnO2-OHads to regenerate the active sites. This research highlights the significance of introducing metal oxides into the nanostructure interface, and the performance of Pd-containing catalysts towards ethanol oxidation reaction was greatly improved.

Three-dimensional PdCuM (M = Ru, Rh, Ir) Trimetallic Alloy Nanosheets for Enhancing Methanol Oxidation Electrocatalysis.

Owing to their intrinsically high activity and rich active sites on the surface, noble metal materials with an ultrathin two-dimensional nanosheet structure are emerging as ideal catalysts for boosting fuel cell reactions. However, the realization of controllable synthesis of multimetallic Pd-based alloy ultrathin nanosheets (NSs) for achieving enhanced electrocatalysis evolved from compositional and structural advantages remains a grand challenge. Herein, we report a universal method for the construction of a new series of the three-dimensional (3D) multimetallic PdCuM (M = Ru, Rh, Ir) superstructures that consist of ultrathin alloy NSs. Different from the conventional 2D ultrathin nanostructure, the 3D PdCuM NSs that endowed with abundant routes for fast mass transport, high noble material utilization efficiency, and ligand effect from M to PdCu display large promotion in electrocatalytic performance for the methanol oxidation reaction. Impressively, the composition-optimized Pd59Cu33Ru8 NSs, Pd57Cu34Rh9 NSs, and Pd63Cu29Ir8 NSs show the mass activities of 1660.8, 1184.4, and 1554.8 mA mg-1 in alkaline media, which are 4.9, 3.5, and 4.6-fold larger than that of commercial Pd/C, respectively. More importantly, all of the PdCuM NSs are also very stable for long-term electrochemical tests.

Ultrafine PtCuRh nanowire catalysts with alleviated poisoning effect for efficient ethanol oxidation.

As a green power source, direct ethanol fuel cells (DEFCs) have broad application prospects. However, most catalysts of DEFCs still exhibit defects, such as the difficulty of C-C bond cleavage, serious CO poisoning and limited catalytic activity. Here, we report ultrafine PtCuRh nanowires (NWs) with outstanding anti-CO-poisoning properties and enhanced activity. The average diameter of the ultrafine PtCuRh NWs is about 1.49 nm, effectively improving the atomic utilization efficiency (UE) of platinum. Owing to the combination of an ultrafine nanostructure, good electronic interaction and the high UE of Pt atoms, the optimized ultrafine PtCuRh NWs/C display superior electrocatalytic activity and stability compared with commercial Pt/C for the ethanol oxidation reaction (EOR). More importantly, further electrochemical results demonstrate that the incorporation of Rh is beneficial for enhancing the antipoisoning capability for some CO-like intermediates. Meanwhile, the synthetic method in this report is robust and universal, and can also be applied to the synthesis of ultrafine trimetallic PtCuPd and PtCuIr nanowires.

Superior Ethanol Oxidation Electrocatalysis Enabled by Ternary Pd-Rh-Te Nanotubes.

Designing and elaborating cost-efficient Pd-based electrocatalysts for direct ethanol fuel cells is thought to be a significant approach to obliterating the challenge of large-scale practical application of fuel cells. Herein, our group creates a novel class of one-dimensional (1D) PdRhTe nanotubes (NTs) by using H2PdCl4 and RhCl3 as metal precursors and Te nanowires (NWs) as the reductant and sacrificial template. Strikingly, the as-obtained PdRhTe ternary nanomaterials with a unique 1D nanotube structure display a high specific activity of 6.53 mA cm-2 and a mass activity of 2039.2 mA mg-1 for the ethanol oxidation reaction (EOR) in alkaline media, which are 1.25 (1.6) and 1.77 (8.0) times those of PdTe/C and (Pd/C), respectively. More significantly, further electrochemical measurements such as CA and successive CV confirm that the optimized PdRhTe NTs display desirable durability and negligible activity decay. Taking advantage of physicochemical characterizations and electrochemical measurements, we reasonably reveal that the outstanding electrocatalytic performances are derived from the unique geometric structure and synergistic effect. The introduction of Rh facilitates the cleavage of C-C bonds, increasing the self-stability of PdRhTe NTs. In general terms, this work should provide new orientations to synthesize cost-efficient electrocatalysts by a sacrificial template method.

Three-dimensional palladium-rhodium nanosheet assemblies: Highly efficient catalysts for methanol electrooxidation.

Even though substantial attention has been focused on exploring promising palladium-based catalysts, the creation of electrocatalysts with simultaneous high activity and reduced cost for fuel cell reactions remains a challenge. Here, we report on the design and construction of a new class of three-dimensional (3D) palladium-rhodium (PdRh) nanosheet assembly (NSA) catalysts through a seed-mediated growth method. Interestingly, the well-defined NSAs with optimized electronic structures and highly open 3D structures exhibit greatly enhanced electrocatalytic activity toward the methanol oxidation reaction (MOR). In particular, optimized Pd86Rh14 NSAs have a mass activity of 1672.7 mA mg-1 for the MOR, 5.4 times higher than that of commercial Pd/C catalysts (303.8 mA mg-1). More importantly, these PdRh NSAs also display improved MOR stability, with stable high electrocatalytic performance for more than 250 potential cycles.