Strong metal–support interaction boosts the electrocatalytic hydrogen evolution capability of Ru nanoparticles supported on titanium nitride

Ruthenium(Ru)has been regarded as one of the most promising alternatives to substitute Pt for catalyzing alkaline hydrogen evolution reaction(HER),owing to its inherent high activity and being the cheapest platinum-group metal.Herein,based on the idea of strong metal–support interaction(SMSI)regulation,Ru/TiN catalysts with different degrees of TiN overlayer over Ru nanoparticles were fabricated,which were applied to the alkaline electrolytic water.Characterizations reveal that the TiN overlayer would gradually encapsulate the Ru nanoparticles and induce more electron transfer from Ru nanoparticles to TiN support by the Ru–N–Ti bond as the SMSI degree increased.Further study shows that the exposed Ru–TiN interfaces greatly promote the H_(2) desorption capacity.Thus,the Ru/TiN-300 with a moderate SMSI degree exhibits excellent HER performance,with an overpotential of 38 mV at 10 mA cm^(−2).Also,due to the encapsulation role of TiN overlayer on Ru nanoparticles,it displays super long-term stability with a very slight potential change after 24 h.This study provides a deep insight into the influence of the SMSI effect between Ru and TiN on HER and offers a novel approach for preparing efficient and stable HER electrocatalysts through SMSI engineering.

Effect of IB-metal on Ni/SiO2 catalyst for selective hydrogenation of acetylene

The IB metal(Au,Ag and Cu)alloyed Pd single atom catalysts had been proved to be efficient in promoting the selectivity for hydrogenation of acetylene to ethylene.As a base metal in the same group as Pd,the Ni-based catalysts are also active for hydrogenation reactions.Herein,the effects of the IB metals on the Ni/SiO2 catalyst for the selective hydrogenation of acetylene were systematically studied.Different from the Pd/SiO2 catalyst,the monometallic Ni/SiO2 catalyst is not active at low temperatures.The addition of the IB metals to the Ni/SiO2 catalysts can greatly enhance the activity.Besides,the catalytic activity of the AuNix/SiO2 and CuNix/SiO2 catalysts increase with the reduction temperature,while the AgNix/SiO2 catalysts are not sensitive to the pretreatment temperature.The origin of the effect of the different IB metals on the Ni-based catalysts for selective hydrogenation of acetylene is discussed based on the characterizations by XRD,TPR and microcalorimetric measurements.

SiO_2-supported Au-Ni bimetallic catalyst for the selective hydrogenation of acetylene

Supported Au catalysts have been reported to exhibit high ethylene selectivity in the hydrogenation of acetylene,but the conversion is relatively low.Adding a second metal to Au has proven to be a promising approach to enhance its catalytic performance in acetylene hydrogenation.In this work,SiO2‐supported Au‐Ni bimetallic catalysts were synthesized and investigated in the selective hydrogenation of acetylene.The Au‐Ni bimetallic catalysts exhibited much higher catalytic performance than that of the corresponding monometallic Au or Ni catalysts.By tuning the reduction temperature and/or Ni loading,we obtained an Au‐Ni/SiO2catalyst with optimal performance.The results of transmission electron microscopy imaging revealed that the Au‐Ni bimetallic particles were highly dispersed on the SiO2support.Meanwhile,analysis of the bimetallic catalyst by energy‐dispersive X‐ray spectroscopy,high‐resolution transmission electron microscopy,and in situ diffuse reflectance infrared Fourier transform spectroscopy demonstrated the formation of Au‐Ni alloy,which contributed to the synergistic effect between Au and Ni in the hydrogenation of acetylene.

Isolation of Pd atoms by Cu for semi-hydrogenation of acetylene: Effects of Cu loading

Cu‐alloyed Pd single‐atom catalysts exhibit excellent catalytic performance for the semi‐hydrogenation of acetylene;however,the limit of the Cu/Pd atomic ratio for forming the alloyed Pd single‐atom catalyst is ambiguous.Herein,silica‐supported Cu-Pd bimetallic catalysts with fixed Pd content and varied Cu loadings were synthesized using an incipient wetness co‐impregnation method.The X‐ray absorption spectroscopy results indicated that Pd formed an alloy with Cu after reduction at250°C and that the Pd atoms were completely isolated by Cu for Cu/Pd atomic ratios≥40/1.Notably,increasing the reduction temperature from250to400°C hardly affected the catalytic performances of the Cu-Pd/SiO2catalysts.This finding can be attributed to the similar chemical environments of Pd demonstrated by the X‐ray absorption spectroscopy results.