Alam Md Kawsar, Mohanta Manish Kumar, White Daulton, Baker Jordon, Graves Lisa S, Jena Puru, Arachchige Indika U
Department of Chemistry, Virginia Commonwealth University, Richmond, VA 23284-2006, United States of America.
Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2041, United States of America.
Nanotechnology. 2025 May 13;36(22). doi: 10.1088/1361-6528/add26f.
The viability of the electrolysis of water currently relies on expensive catalysts such as Pt that are far too impractical for industrial scale use. Thus, there is considerable interest in developing low-cost, earth-abundant nanomaterials and their alloys as a potential alternative to existing standard catalysts. To address this issue, a synergistic approach involving theory and experiment was carried out. The former, based on density functional theory, was conducted to guide the experiment in selecting the ideal dopant and optimal concentration by focusing on 3d, 4d, and 5d elements as dopants on Ni (001) surface. Subsequently, a series of NiCr(= 0.01-0.09) alloy nanocrystals (NCs) with size ranging from 8.3 ± 1.6-18.2 ± 3.2 nm were colloidally synthesized to experimentally investigate the hydrogen evolution reaction (HER) activity. A compositional dependent trend for electrocatalytic activity was observed from both approaches with NiCrNCs showed the lowest Δvalue and the lowest overpotential () at -10 mA cmcurrent density (), suggesting the highest HER activity among all compositions studied. Among alloy NCs, the highest performing NiCrcomposition displayed a mixed Volmer-Heyrovsky HER mechanism, the lowest Tafel slope, and improved stability in alkaline solutions. This study provides critical insights into enhancing the performance of earth-abundant metals through doping-induced electronic structure variation, paving the way for the design of high-efficiency catalysts for water electrolysis.
目前，水电解的可行性依赖于昂贵的催化剂，如铂，这对于工业规模应用来说极不实用。因此，人们对开发低成本、储量丰富的纳米材料及其合金作为现有标准催化剂的潜在替代品有着浓厚兴趣。为解决这一问题，开展了一种理论与实验相结合的协同方法。前者基于密度泛函理论，通过聚焦于作为镍（001）表面掺杂剂的3d、4d和5d元素，来指导实验选择理想的掺杂剂和最佳浓度。随后，胶体合成了一系列尺寸范围为8.3±1.6 - 18.2±3.2纳米的NiCr（= 0.01 - 0.09）合金纳米晶体（NCs），以实验研究析氢反应（HER）活性。从两种方法中都观察到了电催化活性的成分依赖性趋势，其中NiCrNCs在-10 mA cm电流密度（）下显示出最低的Δ值和最低的过电位（），表明在所研究的所有成分中具有最高的HER活性。在合金NCs中，性能最佳的NiCr成分表现出混合的Volmer - Heyrovsky析氢反应机理、最低的塔菲尔斜率以及在碱性溶液中提高的稳定性。这项研究为通过掺杂诱导电子结构变化来提高储量丰富金属的性能提供了关键见解，为设计高效水电解催化剂铺平了道路。
