Zou Yan, Jin Man, Zhu Dongdong, Tang Yu-Jia
School of Chemistry and Materials Science, Institute of Advanced Materials and Flexible Electronics (IAMFE), Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing 210044, P.R. China.
Inorg Chem. 2023 Sep 25;62(38):15757-15765. doi: 10.1021/acs.inorgchem.3c02683. Epub 2023 Sep 14.
Developing highly active and cost-effective electrocatalysts is critical for enhancing the intrinsic performance of electrocatalytic water splitting. Oxoanion-based compounds, such as phosphates and molybdates, have emerged as promising electrocatalysts owing to their advantageous properties of nontoxicity, low price, and strong water adsorption ability. However, their relatively inferior activity has impeded extensive investigation into electrochemical applications. Herein, an amorphous phosphate-adsorbed and RuNi-doped molybdate (RuNiMo-P) composite is synthesized on nickel foam (NF) support by using a simple two-step method. Significantly, an acidic solution of phosphomolybdic acid (PMo), containing a low concentration of Ru, can etch the NF, contributing to the in situ growth of the RuNi-doped molybdate precursor. Subsequent phosphating ensures the surface formation of the amorphous phosphate layer due to abundant oxygen in the precursor. The strong structural interaction between RuNi-doped molybdate and amorphous phosphate in RuNiMo-P prompts an enhanced hydrogen evolution reaction (HER) performance, delivering an overpotential of 38 mV at a current density of -10 mA cm, a Tafel slope of 53 mV dec, and good stability in an alkaline medium. Characterizations after HER reveal that RuNi doping, partial dissolution of phosphate and molybdate species, and newly formed NiOOH nanosheets can expose active sites, facilitate charge transfer, and modify electronic structures, thereby improving the HER performance effectively.
开发高活性和高性价比的电催化剂对于提高电催化水分解的本征性能至关重要。基于含氧阴离子的化合物，如磷酸盐和钼酸盐，由于其无毒、价格低廉和强水吸附能力等优势，已成为有前景的电催化剂。然而，它们相对较差的活性阻碍了对其电化学应用的广泛研究。在此，通过一种简单的两步法在泡沫镍（NF）载体上合成了一种无定形磷酸盐吸附且RuNi掺杂的钼酸盐（RuNiMo-P）复合材料。值得注意的是，含有低浓度Ru的磷钼酸（PMo）酸性溶液可以蚀刻NF，有助于RuNi掺杂的钼酸盐前驱体的原位生长。随后的磷化处理由于前驱体中丰富的氧确保了无定形磷酸盐层在表面形成。RuNiMo-P中RuNi掺杂的钼酸盐与无定形磷酸盐之间强烈的结构相互作用促使析氢反应（HER）性能增强，在电流密度为-10 mA cm时过电位为38 mV，塔菲尔斜率为53 mV dec，并且在碱性介质中具有良好的稳定性。HER后的表征表明，RuNi掺杂、磷酸盐和钼酸盐物种的部分溶解以及新形成的NiOOH纳米片可以暴露活性位点、促进电荷转移并改变电子结构，从而有效地提高HER性能。
