The discovery and identification of novel active sites are paramount for deepening the understanding of the catalytic mechanism and driving the development of remarkable electrocatalysts. Here, we reveal that the genuine active sites for the hydrogen evolution reaction (HER) in LaRuSi are Si sites, not the usually assumed Ru sites. Ru in LaRuSi has a peculiar negative valence state, which leads to strong hydrogen binding to Ru sites. Surprisingly, the Si sites have a Gibbs free energy of hydrogen adsorption that is near zero (0.063 eV). The moderate adsorption of hydrogen on Si sites during the HER process is also validated by in situ Raman analysis. Based on it, LaRuSi exhibits an overpotential of 72 mV at 10 mA cm-2 in alkaline media, which is close to the benchmark of Pt/C. This work sheds light on the recognition of real active sites and the exploration of innovative silicide HER electrocatalysts.

Highly Active Si Sites Enabled by Negative Valent Ru for Electrocatalytic Hydrogen Evolution in LaRuSi.

Manipulating the active species and improving the structural stabilization of sulfur-containing catalysts during the OER process remain a tremendous challenge. Herein, we constructed NiO/NiS 2 and Fe - NiO/NiS 2 as catalyst models to study the effect of Fe doping. As expected, Fe - NiO/NiS 2 exhibits a low overpotential of 270 mV at 10 mA cm -2 . The accumulation of hydroxyl groups on the surface of materials after Fe doping can promote the formation of high active NiOOH at a lower OER potential. Moreover, we investigated the level of corrosion of M-S bonds and compared the stability variation of M-S bonds with Fe at different locations. Interestingly, Fe bonded with S in the bulk as the sacrificial agent can alleviate the oxidation corrosion of partial Ni-S bonds and thus endow Fe - NiO/NiS 2 long-term durability. This work would motivate the community to focus more on resolving the corrosion of sulfur-containing materials.

Surface Activation and Ni-S Stabilization in NiO/NiS2 for Efficient Oxygen Evolution Reaction.

Exploring the hydrogen evolution catalytic activity of the orthorhombic and hexagonal borophene as the hydrogen storage material

Exploring highly active and cost-efficient single-atom catalysts (SACs) for oxygen reduction reaction (ORR) is critical for the large-scale application of Zn-air battery. Herein, density functional theory (DFT) calculations predict that the intrinsic ORR activity of the active metal of SACs follows the trend of Co > Fe > Ni ≈ Cu, in which Co SACs possess the best ORR activity due to its optimized spin density. Guided by DFT calculations, four kinds of transition metal single atoms embedded in 3D porous nitrogen-doped carbon nanosheets (MSAs@PNCN, M = Co, Ni, Fe, Cu) are synthesized via a facile NaCl-template assisted strategy. The resulting MSAs@PNCN displays ORR activity trend in lines with the theoretical predictions, and the Co SAs@PNCN exhibits the best ORR activity (E1/2  = 0.851 V), being comparable to that of Pt/C under alkaline conditions. X-ray absorption fine structure (XAFS) spectra verify the atomically dispersed Co-N4 sites are the catalytically active sites. The highly active CoN4 sites and the unique 3D porous structure contribute to the outstanding ORR performance of Co SAs@PNCN. Furthermore, the Co SAs@PNCN catalyst is employed as cathode in Zn-air battery, which can deliver a large power density of 220 mW cm-2 and maintain robust cycling stability over 530 cycles.

Transition Metal (Co, Ni, Fe, Cu) Single-Atom Catalysts Anchored on 3D Nitrogen-Doped Porous Carbon Nanosheets as Efficient Oxygen Reduction Electrocatalysts for Zn-Air Battery.

Defective WO3 nanoplates controllably decorated with MIL-101(Fe) nanoparticles to efficiently remove tetracycline hydrochloride by S-scheme mechanism

Alloying noble metals with non‐noble metals is a promising method to fabricate catalysts, with the advantages of reduced noble metal usage and excellent activity. In this work, electron‐abundant Ir/Rh sites, as highly active centers for the hydrogen evolution reaction (HER), are realized by fabricating Ir1−xRhxSb alloys through the arc‐melting method. The electron transfer from Sb to Ir/Rh makes the latter negatively charged, leading to considerably optimized adsorption for active H species during HER. As a result, the Ir1−xRhxSb alloy exhibits outstanding activity for HER, with an optimized overpotential of 22 mV at 10 mA cm–2 and a Tafel slope of 47.6 mV dec–1. This work provides insights into highly active alloys and sheds light on the utilization of electron‐abundant metal atoms.

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir1−xRhxSb Intermetallic Alloy for Hydrogen Evolution Reaction

Water Splitting In article number 2200855, Wenwu Zhong and co-workers prepare ternary intermetallic Ir1−xRhxSb alloys with negatively charged metal sites, using the arc-melting method, to achieve advanced electrocatalytic activity for the hydrogen evolution reaction. This work provides insights into highly active alloys and sheds light on the utilization of electron-abundant metal atoms. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/aenm.202270108

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir
 1−
 
 x
 
 Rh
 
 x
 
 Sb Intermetallic Alloy for Hydrogen Evolution Reaction (Adv. Energy Mater. 25/2022)

Using SBA-15 molecular sieve as the support, Cu/SBA-15 and Cu-ZnO/SBA-15 catalysts were prepared by grinding and impregnation. They were characterized by XRD, TEM, TPR and nitrogen adsorption/desorption methods. Their catalytic activities of the dehydrogenation of methanol to methyl formate (MF) were studied and compared.The results indicated that the Cu and ZnO in the catalysts prepared by grinding had a worse dispersity than that prepared by impregnation. However, the reduction temperature of the CuO in the catalysts prepared by grinding was obviously lower than that prepared by impregnation and the selectivity to MF can be improved with the adding of ZnO. The experiments showed that the methanol conversion rate and selectivity to MF were 15.23% and 79.81% at 270°C for Cu-ZnO/SBA-15-G prepared by grinding, respectively. For Cu-ZnO/SBA-15-I prepared by impregnation, the methanol conversion rate and selectivity to MF were 13.41 % and 81.31% respectively.

Min Jian Huang

Papers

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir1−xRhxSb Intermetallic Alloy for Hydrogen Evolution Reaction

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir 1− x Rh x Sb Intermetallic Alloy for Hydrogen Evolution Reaction (Adv. Energy Mater. 25/2022)

Catalytic Activity of Dehydrogenation of Methanol to MF over Cu/SBA-15 and Cu-ZnO/SBA-15 Prepared by Grinding and Impregnation