Morishita M, Nozaki A, Yamamoto H, Fukumuro N, Mori M, Araki K, Sakamoto F, Nakamura A, Yanagita H
Department of Chemical Engineering and Materials Science, University of Hyogo 2167 Shosha Himeji 671-2280 Japan
Graduate Student of University of Hyogo 2167 Shosha Himeji 671-2280 Japan.
RSC Adv. 2021 Apr 14;11(23):14063-14070. doi: 10.1039/d1ra01181b. eCollection 2021 Apr 13.
Pt is an excellent and widely used hydrogen evolution reaction (HER) catalyst. However, it is a rare and expensive metal, and alternative catalysts are being sought to facilitate the hydrogen economy. As tungsten carbide (WC) has a Pt-like occupied density of states, it is expected to exhibit catalytic activity. However, unlike Pt, excellent catalytic activity has not yet been observed for mono WC. One of the intrinsic differences between WC and Pt is in their magnetic properties; WC is non-magnetic, whereas Pt exhibits high magnetic susceptibility. In this study, the WC lattice was doped with ferromagnetic Co nanocrystals to introduce an ordered-spin atomic configuration. The catalytic activity of the Co-doped WC was ∼30% higher than that of Pt nanoparticles for the HER during the hydrolysis of ammonia borane (NHBH), which is currently attracting attention as a hydrogen fuel source. Measurements of the magnetisation, enthalpy of adsorption, and activation energy indicated that the synergistic effect of the WC matrix promoting hydrolytic cleavage of NHBH and the ferromagnetic Co crystals interacting with the nucleus spin of the protons was responsible for the enhanced catalytic activity. This study presents a new catalyst design strategy based on the concept of an internal magnetic field. The WC-Co material presented here is expected to have a wide range of applications as an HER catalyst.
铂是一种优异且广泛使用的析氢反应（HER）催化剂。然而，它是一种稀有且昂贵的金属，因此人们正在寻找替代催化剂以推动氢能经济发展。由于碳化钨（WC）具有类似铂的占据态密度，预计它会表现出催化活性。然而，与铂不同的是，尚未观察到单碳化钨具有优异的催化活性。碳化钨和铂之间的一个内在差异在于它们的磁性；碳化钨是非磁性的，而铂表现出高磁化率。在本研究中，碳化钨晶格被铁磁钴纳米晶体掺杂，以引入有序自旋原子构型。在氨硼烷（NHBH）水解过程中，对于析氢反应，钴掺杂碳化钨的催化活性比铂纳米颗粒高约30%，氨硼烷目前作为一种氢燃料源正受到关注。磁化强度、吸附焓和活化能的测量表明，碳化钨基体促进氨硼烷水解裂解的协同效应以及铁磁钴晶体与质子核自旋的相互作用是催化活性增强的原因。本研究基于内磁场概念提出了一种新的催化剂设计策略。这里展示的碳化钨 - 钴材料有望作为析氢反应催化剂有广泛的应用。
