电催化剂
过电位
塔菲尔方程
石墨烯
氧化物
材料科学
合金
交换电流密度
双金属片
化学工程
纳米复合材料
纳米颗粒
析氧
催化作用
无机化学
纳米技术
化学
电极
电化学
复合材料
冶金
有机化学
金属
物理化学
工程类
作者
Gitashree Darabdhara,Manash R. Das,Mohammed A. Amin,Gaber A.M. Mersal,Nasser Y. Mostafa,Sayed S. Abd El‐Rehim,Sabine Szunerits,Rabah Boukherroub
标识
DOI:10.1016/j.ijhydene.2017.11.048
摘要
Bimetallic nanoparticles of Au and Ni in the form of alloy nanostructures with varying Ni content are synthesized on reduced graphene oxide (rGO) sheets via a simple solution chemistry route and tested as electrocatalysts towards the hydrogen evolution (HE) and oxygen reduction (OR) reactions using polarization and impedance studies. The AuNi alloy NPs/rGO nanocomposites display excellent electrocatalytic activity which is found to improve with increasing Ni content in the AuNi/rGO alloy nanocomposites. For HER, the best AuNi alloy NPs/rGO electrocatalyst, the one with the highest Ni content, exhibits high activity with an onset overpotential approaching zero versus the reversible hydrogen electrode and an overpotential of only 37 mV at 10 mA cm−2. Additionally, a low Tafel slope of 33 mV dec−1 and a high exchange current density of 0.6 mA cm−2 are measured which are very close to those of commercial Pt/C catalyst. Also, in the ORR tests, this electrocatalyst displays comparable activity to Pt/C. The Koutecky–Levich plots referred to a 4-electron mechanism for the reduction of dissolved O2 on the AuNi alloy NPs/rGO catalyst. The electrocatalyst thus demonstrates excellent activity towards HER and ORR. Additionally, it exhibits outstanding operational durability and activation after 10,000th cycles assuring its practical applicability.
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