A Multisite Strategy for Enhancing the Hydrogen Evolution Reaction on a Nano‐Pd Surface in Alkaline Media. Issue 21 (7th August 2017)

• Record Type: Journal Article
• Authors: Liao, Hanbin; Wei, Chao; Wang, Jingxian; Fisher, Adrian; Sritharan, Thirumany; Feng, Zhenxing; Xu, Zhichuan J.
• Is Part Of: Advanced energy materials. Volume 7:Issue 21(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-08-07
• Subjects: electrocatalysis -- hydrogen evolution reaction -- multisite -- nanoparticle -- surface coverage; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201701129
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: The hydrogen evolution reaction (HER) on a noble metal surface in alkaline media is more sluggish than that in acidic media due to the limited proton supply. To promote the reaction, it is necessary to transform the alkaline HER mechanism via a multisite catalyst, which has additional water dissociation sites to improve the proton supply to an optimal level. Here, this study reports a top‐down strategy to create a multisite HER catalyst on a nano‐Pd surface and how to further fine‐tune the areal ratio of the water dissociation component to the noble metal surface in core/shell‐structured nanoparticles (NPs). Starting with Pd/Fe3 O4 core/shell NPs, electrochemical cycling is used to tune the coverage of iron (oxy)hydroxide on a Pd surface. The alkaline HER activity of the core/sell Pd/FeO x (OH)2−2 x NPs exhibits a volcano‐shaped correlation with the surface Fe species coverage. This indicates an optimum coverage level where the rates of both the water dissociation step and the hydrogen formation step are balanced to achieve the highest efficiency. This multisite strategy assigns multiple reaction steps to different catalytic sites, and should also be extendable to other core/shell NPs to optimize their HER activity in alkaline media. Abstract : A Pd/FeO x (OH)2−2 x heterostructure is fabricated by electrochemical cycling starting from Pd/Fe3 O4 core/shell nanoparticles. The optimum FeO x (OH)2−2 x coverage can balance the rates of both the water dissociation step and the hydrogen formation step for hydrogen evolution reaction in alkaline to reach the highest electrocatalytic efficiency.