Active sites engineering of Pt/CNT oxygen reduction catalysts by atomic layer deposition

Understanding carbon-supported Pt-catalyzed oxygen reduction reaction(ORR)from the perspective of the active sites is of fundamental and practical importance.In this study,three differently sized carbon nanotube-supported Pt nanoparticles(Pt/CNT)are prepared by both atomic layer deposition(ALD)and impregnation methods.The performances of the catalysts toward the ORR in acidic media are comparatively studied to probe the effects of the sizes of the Pt nanoparticles together with their distributions,electronic properties,and local environments.The ALD-Pt/CNT catalysts show much higher ORR activity and selectivity than the impregnation-Pt/CNT catalysts.This outstanding ORR performance is ascribed to the well-controlled Pt particle sizes and distributions,desirable Pt^04f binding energy,and the Cl-free Pt surfaces based on the electrocatalytic measurements,catalyst characterizations,and model calculations.The insights reported here could guide the rational design and fine-tuning of carbon-supported Pt catalysts for the ORR.

SDS-modified Nanoporous Silver as an Efficient Electrocatalyst for Selectively Converting CO2 to CO in Aqueous Solution

Selectively electrochemical conversion of CO2 into organic fuel using renewable electricity is one of the most sought-after processes.In this paper,we report the electrochemical reduction of CO2(CO2RR)on the nanoporous Ag electrodes made of compacted Ag nanoparticles(AgNPs),which were prepared by one-step reduction in the water phase with or without the surfactant sodium dodecyl sulfate(SDS).The scanning electron microscope(SEM)characterizations show that the compacted Ag electrodes have the nanoporous morphology formed by stacking AgNPs.Compared with the nanoporous Ag electrode without SDS modification(C-AgNPs),the SDS-modified AgNPs electrode(C-AgNPs-SDS)is highly effective in improving selective CO production in a wide range of potentials(-0.69 V--1.19 V,vs.RHE),with a Faradaic efficiency of 92.2% and a current density of -8.23 mA·cm^-2 for CO production at -0.79 V(vs.RHE).C-AgNPs-SDS is also catalytically stable with only less than 7% deactivation after 8 h of continuous electrolysis.