Hydrogen Spillover Accelerates Electrocatalytic Semi-hydrogenation of Acetylene in Membrane Electrode Assembly Reactor.

Electrocatalytic acetylene semi-hydrogenation (EASH) offers a promising and environmentally friendly pathway for the production of C2H4, a widely used petrochemical feedstock. While the economic feasibility of this route has been demonstrated in three-electrode systems, its viability in practical device remains unverified. In this study, we designed a highly efficient electrocatalyst based on a PdCu alloy system utilizing the hydrogen spillover mechanism. The catalyst achieved an operational current density of 600 mA cm-2 in a zero-gap membrane electrode assembly (MEA) reactor, with the C2H4 selectivity exceeding 85%. This data confirms the economic feasibility of EASH in real-world applications. Furthermore, through in situ Raman spectroscopy and theoretical calculations, we elucidated the catalytic mechanism involving interfacial hydrogen spillover. Our findings underscore the economic viability and potential of EASH as a greener and scalable approach for C2H4 production, thus advancing the field of electrocatalysis in sustainable chemical synthesis.

Genomics and LC-MS Reveal Diverse Active Secondary Metabolites in Bacillus amyloliquefaciens WS-8.

Bacillus amyloliquefaciens is an important plant disease-preventing and growth-promoting microorganism. B. amyloliquefaciens WS-8 can stimulate plant growth and has strong antifungal properties. In this study, we sequenced the complete genome of B. amyloliquefaciens WS-8 by Pacific Biosciences RSII (PacBio) Single Molecule Real-Time (SMRT) sequencing. The genome consists of one chromosome (3,929,787 bp) and no additional plasmids. The main bacteriostatic substances were determined by genome, transcriptome, and mass spectrometry data. We thereby laid a theoretical foundation for the utilization of the strain. By genomic analysis, we identified 19 putative biosynthetic gene clusters for secondary metabolites, most of which are potentially involved in the biosynthesis of numerous bioactive metabolites, including difficidin, fengycin, and surfactin. Furthermore, a potential class II lanthipeptide biosynthetic gene cluster and genes that are involved in auxin biosynthesis were found. Through the analysis of transcriptome data, we found that the key bacteriostatic genes, as predicted in the genome, exhibited different levels of mRNA expression. Through metabolite isolation, purification, and exposure experiments, we found that a variety of metabolites of WS-8 exert an inhibitory effect on the necrotrophic fungus Botrytis cinerea, which causes gray mold; by mass spectrometry, we found that the main substances are mainly iturins and fengycins. Therefore, this strain has the potential to be utilized as an antifungal agent in agriculture.

Nickel Promoted Palladium Nanoparticles for Electrocatalysis of Carbohydrazide Oxidation Reaction.

Carbohydrazide is a potential alternative to toxic hydrazine for fuel cell applications to overcome the challenges of storage and transportation of hydrogen. In this work, Ni-alloyed Pd nanoparticles (NPs) with varied Pd-Ni ratios supported on carbon black (PdNix /C) are prepared and their catalytic performance for the carbohydrazide electro-oxidation reaction is investigated. The catalytic performance of PdNix /C NPs is significantly improved in comparison to Pd/C NPs. The current density of PdNix /C NPs with optimized Pd-Ni atom ratio can reach 3.26 A mg-1 metal at a potential of 0.4 V (vs reversible hydrogen electrode), which is an increase of 2.4 times compared to that of Pd/C. The density functional theory calculation indicates the enhanced catalytic activity is caused by the change of adsorption energy of carbohydrazide molecules on the metal surface. It exhibits a volcano relationship between the adsorption energy and the catalytic current density of PdNix /C with varied Pd-Ni atom ratios.

Eco-friendly synthesis of N,S co-doped hierarchical nanocarbon as a highly efficient metal-free catalyst for the reduction of nitroarenes.

Heteroatom-doped carbon nanomaterials are effective metal-free catalysts for organic reactions. However, S-doped carbocatalysts are relatively unexplored due to challenges related to the synthesis of S-doped nanocarbon. Herein, we employed a facile, low-cost and eco-friendly approach to construct a N,S co-doped hierarchical carbon nanomaterial (NSHC) via the pyrolysis of an azo-sulphonate dye pollutant intercalated layered double hydroxide. The as-prepared NSHC possesses a two-dimensional hierarchical porous structure with ultrathin carbon nanosheets uniformly distributed on hexagonal carbon nanoplates, endowing the material with a high specific surface area of 1260 m2 g-1. Attributed to the synergistic effects of N,S co-doping, the high specific surface area and the interconnected porous architecture, NSHC demonstrates excellent catalytic activity and selectivity in the reduction of nitroarenes. Among the reported carbocatalysts for nitrobenzene reduction using hydrazine hydrate, NSHC shows the highest turnover frequency value of 4.89 h-1. Furthermore, NSHC exhibits remarkable recyclability and generality for the reduction of various aromatic nitro compounds.

An efficient cluster model to describe the oxygen reduction reaction activity of metal catalysts: a combined theoretical and experimental study.

A simple and efficient cluster model containing only seven metal atoms was proposed to investigate the oxygen reduction reaction (ORR) activity of various metal catalysts by density functional theory (DFT) calculation. The model was validated by comparing ORR volcano plots obtained from the cluster model in this work and the slab model in the literature. We then used this model to investigate the influence of the support of Ag nanoparticles on ORR activity, which is hard to describe by the slab model. The calculations revealed the binding energy of oxygen atoms on Ag/COOH-CNTs or Ag/OH-CNTs changed to 2.04 and 2.09 eV respectively, in comparison to that of Ag/CNTs (2.13 eV). As a result, the ORR current density improved to 2.24 and 1.88 mA cm-2 at the potential of 0.7 V (vs. RHE) for Ag/COOH-CNTs and Ag/OH-CNTs respectively, in comparison to that of Ag/CNTs (1.66 mA cm-2). The cluster model could simultaneously reduce the computing time and make it possible to consider the influence of catalyst supports, which would provide new insight to design more effective ORR metal catalysts.