Ultralow RuO2 Doped NiS2 Heterojunction as a Multifunctional Electrocatalyst for Hydrogen Evolution linking to Biomass Organics Oxidation.

Hydrogen energy and biomass energy are green and sustainable forms that can solve the energy crisis all over the world. Electrocatalytic water splitting is a marvelous way to produce hydrogen and biomass platform molecules can be added into the electrolyte to reduce the overpotential and meanwhile are converted into some useful organics, but the key point is the design of electrocatalyst. Herein, ultralow noble metal Ru is doped into NiS2 to form RuO2@NiS2 heterojunction. Amongst them, the 0.06 RuO2@NiS2 has low overpotentials of 363 mV for OER and 71 mV for HER in 1 m KOH, which are superior to the RuO2 and Pt/C. Besides, the 0.06 RuO2@NiS2 shows a low overpotential of 173 mV in 1 m KOH+0.1 m glycerol, and the glycerol is oxidized to glyceraldehyde and formic acid via the high Faraday efficiency GlyOR process, and the splitting voltage is only 1.17 V. In addition, the 0.06 RuO2@NiS2 has a low overpotential of 206 mV in 1 m KOH+0.1 m glucose, and the glucose is converted to glucaric acid, lactic acid, and formic acid. This work has a "one stone three birds" effect for the production of hydrogen, low splitting voltage, and high-value-added biomass chemicals.

Ag Nanoparticles and Rod-Shaped AgCl Decorated Porous PEDOT as a Bifunctional Material for Hydrogen Evolution Catalyst and Supercapacitor Electrode.

PEDOT-Ag/AgCl is a highly promising material with dual functions of hydrogen evolution reaction (HER) and supercapacitors. In this study, a simple low-temperature stirring and light irradiation method was used to synthesize PEDOT-Ag/AgCl on the surface. Then, PEDOT-Ag/AgCl was analyzed using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. PEDOT-Ag/AgCl reacted in 1 M KOH alkaline electrolyte with an overpotential of 157 mV at 20 mA·cm-2 and a Tafel slope of 66.95 mv·dec-1. Owing to the synergistic effect of PEDOT and Ag/AgCl, this material had a small resistance (1.7 Ω) and a large specific capacitance (978 F·g-1 at current density of 0.5 A·g-1). The synthesis method can prepare nanostructured PEDOT with uniformly-distributed Ag nanoparticles and rod-shaped AgCl on the surface, which can be used as both HER electrocatalysts and supercapacitor electrodes.

Facile Synthesis of Z-Scheme Ag3PO4/Sulfur-Doped g-C3N4 Heterojunction Hybrids with Enhanced Visible Light Photocatalytic Performance.

Ag3PO4/sulfur-doped g-C3N4 heterojunctions were fabricated by the means of a facile calcination and co-precipitation method. Structural characterization suggested that Ag3PO4 was successfully loaded onto sulfur-doped g-C3N4. The absorption band edges of sulfur-doped g-C3N4 were shifted to the longer wavelength in comparison with bulk g-C3N4. The Ag3PO4/sulfur-doped g-C3N4 heterojunctions manifested substantially higher visible-light photocatalytic performance as compared with Ag3PO4/bulk g-C3N4. Photoluminescence spectra suggested that the stable Ag3PO4/SGCN heterojunctions could effectively address the electron-hole recombination rate, together with remarkably enhancing the photocatalytic activity. The enhancement of light absorption and better dispersion in Ag3PO4/sulfur-doped g-C3N4 provide more migration channels, together with posing crucial responsibility for the enhanced photocatalytic performance.

Preparation and properties of lignin-based dual network hydrogel and its application in sensing.

Ionic conductive hydrogels prepared from various biological macromolecules are ideal materials for the manufacture of human motion sensors from the perspective of resource regeneration and environmental sustainability. However, it is now difficult to develop conductive hydrogels including excellent self-healing and mechanical properties, mainly due to their inherent trade-off between dynamic cross-linked healing and stable cross-linked mechanical strength. In this work, alkali lignin-Polyvinyl alcohol-polyacrylic acid double network conductive hydrogels with high mechanical strength and good self-healing properties were prepared. We formed the primary network structure by hydrogen bonding interaction between polyvinyl alcohol, alkali lignin and polyacrylic acid, and the secondary network structure by coordination interaction with polyacrylic acid through the addition of Fe3+. The added lignin acts as a dynamic linkage bridge in a porous network mediated by multiple ligand bonds, imparting superior mechanical properties to the hydrogels. The relationships between the alkali lignin and iron ion dosage and the comprehensive properties of hydrogels (adhesion, antibacterial, self-healing, electrical conductivity and mechanical properties) were studied in detail. On this basis, the hydrogels explored the role of lignin in the regulation of hydrogels properties and revealed the self-healing and conductive mechanism.

Iron clusters regulate local charge distribution in Fe-N4 sites to boost oxygen electroreduction.

The atomically-dispersed and nitrogen-coordinated iron (FeNC) on a carbon catalyst is a potential non-noble metal catalyst that can replace precious metal electrocatalysts. However, its activity is often unsatisfactory owing to the symmetric charge distribution around the iron matrix. In this study, atomically- dispersed Fe-N4 and Fe nanoclusters loaded with N-doped porous carbon (FeNCs/FeSAs-NC-Z8@34) were rationally fabricated by introducing homologous metal clusters and increasing the N content of the support. FeNCs/FeSAs-NC-Z8@34 exhibited a half-wave potential of 0.918 V, which exceeded that of the commercial benchmark Pt/C catalyst. Theoretical calculations verified that introducing Fe nanoclusters can break the symmetric electronic structure of Fe-N4, thus inducing charge redistribution. Furthermore, it can optimize a part of Fe 3d occupancy orbitals and accelerate OO fracture in OOH* (rate-determining step), thus significantly improving oxygen reduction reaction activity. This work provides a reasonably advanced pathway to modulate the electronic structure of the single-atom center and optimize the catalytic activity of single-atom catalysts.

Interface engineering Ni/Ni12P5@CNx Mott-Schottky heterojunction tailoring electrocatalytic pathways for zinc-air battery.

Due to the poor bifunctional electrocatalytic performances of electrocatalysts in zinc-air battery, herein, we first synthesized Ni/Ni12P5@CNx Mott-Schottky heterojunction to ameliorate the high-cost and instability of precious metals. We modulated the different contents of Ni and Ni12P5 in the Ni/Ni12P5@CNx Mott-Schottky heterojunction, and found that 0.6 Ni/Ni12P5@CNx has outstanding electrocatalytic performances, with half-wave potential of 0.83 V, and OER potential of 1.49 V at 10 mA cm-2. Also, the ΔE value is only 0.66 V. Moreover, 0.6 Ni/Ni12P5@CNx is assembled into ZAB, which has a high power density of 181 mW cm-2 and a high specific capacity of 710 mAh g-1. This indicates it has a good cycle stability. The density functional theory (DFT) calculations reveal that electrons spontaneously flow from Ni to Ni12P5 through the formed buffer layer in the Ni/Ni12P5@CNx Mott-Schottky heterojunction. The Schottky barrier formed modulates the electrocatalytic pathway to have good bifunctional electrocatalytic activity for ORR and OER.

A Scientometric Review: Biomass Gasification Study from 2006 to 2020.

Biomass gasification represents a significant way to produce energy from biomass. It features renewable properties and offers great potential for utilization. The application of biomass gasification products, design of the gasifier, type of biomass feedstock, gasification agents, and gasification parameters are key for the biomass gasification process. This work applies bibliometric approaches to provide a comprehensive and objective analysis of worldwide biomass gasification study trends over the period from 2006 to 2020 according to the Web Of Science core collection data. A total of 3222 articles associated with biomass gasification was retrieved, and its number grew annually. The subjects of study are diversified, primarily classified into "Energy & Fuels", "Engineering Chemical", and "Green Sustainable Science Technology". Moreover, Energy was a top published journal in the field of biomass gasification. Austrian contributors had the majority of publications, next to China and the USA. Liejin Luo from Xi'an Jiaotong University possessed the greatest H-index. Keyword evaluation showed that biomass gasification is a current hotspot, among which life-cycle assessment, sustainability, and deep processing of gasification products are future research directions. This work is predicted to offer further research interest in biomass gasification.

Fabrication of lignin reinforced hybrid hydrogels with antimicrobial and self-adhesion for strain sensors.

Ionic conductive hydrogels prepared from various biological macromolecules are ideal materials for the manufacture of human motion sensors from the perspective of resource regeneration and environmental sustainability. However, it is still challenging to prepare hydrogels with both high toughness and self-healing ability. In this study, lignin-based ß-CD-PVA (LCP) self-healing conductive hydrogels with high tensile properties were prepared by one-step method using alkali lignin as a plasticizer. Compared with PVA hydrogel, the maximum storage modulus and elongation were increased by 2.5 and 20.0 times, respectively. Uniform distribution of lignin can increase the fluidity and distance of polymer molecular chains, thus improving the viscoelastic and tensile properties of the LCP self-healing hydrogel. LCP hydrogels can maintain self-healing ability in both high (45 °C) and low temperature (0 °C) environments, and the self-healing ability is not affected by pH. Moreover, it also has good conductivity, anti-bacterial, thermostability, and anti-UV property, which has a good application prospect in the field of 3D printing and wearable electronic devices, which expands the efficient utilization of lignin in biorefinery.

Biochar Nanocomposite Derived from Watermelon Peels for Electrocatalytic Hydrogen Production.

Water splitting is the most potential method to produce hydrogen energy, however, the conventional electrocatalysts encounter the hindrances of high overpotential and low hydrogen production efficiency. Herein, we report a carbon-based nanocomposite (denoted as CCW-x, x stands for the calcination temperature) derived from watermelon peels and CoCl2, and the as-synthesized CCW-x is used as the electrocatalyst. The overpotential and the Tafel slope of CCW-700 for oxygen evolution reaction (OER) is 237 mV at 10 mA cm-2 and 69.8 mV dec-1, respectively, both of which are lower than those of commercial RuO2. For hydrogen evolution reaction (HER), the overpotential of CCW-700 (111 mV) is higher than that of the widely studied Pt/C (73 mV) but still lower than those of lots of carbon-based nanomaterials (122-177 mV). In the light of CCW-700 is highly active for both OER and HER, we assembled a water-splitting electrocatalyst by employing nickel foam loaded with CCW-700 as the anode and cathode in 1 M KOH. The water-splitting voltage is only 1.54 V for the CCW-700//CCW-700 electrodes and 1.62 V for the RuO2//Pt/C ones. Therefore, the so-denoted CCW-x powder possesses good electrocatalytic hydrogen production efficiency.

An Efficient Catalyst Derived from Carboxylated Lignin-Anchored Iron Nanoparticle Compounds for Carbon Monoxide Hydrogenation Application.

Catalytic activity and target product selectivity are strongly correlated to the size, crystallographic phase, and morphology of nanoparticles. In this study, waste lignin from paper pulp industry is employed as the carbon source, which is modified with carboxyl groups at the molecular level to facilitate anchoring of metals, and a new type of carbon-based catalyst was obtained after carbonization. As a result, the size of the metal particles is effectively controlled by the chelation between -COO- and Fe3+. Furthermore, Fe/CM-CL with a particle size of 1.5-2.5 nm shows excellent catalytic performance, the conversion of carbon monoxide reaches 82.3%, and the selectivity of methane reaches 73.2%.