Ji Mengyi, Yaseen Waleed, Mao Huiping, Xia Changkun, Xu Yuanguo, Meng Suci, Xie Jimin, Xie Meng
School of Chemistry and Chemical Engineering, School of Pharmacy, Jiangsu University, Zhenjiang 212013, P. R. China.
Inorg Chem. 2023 Aug 7;62(31):12383-12391. doi: 10.1021/acs.inorgchem.3c01587. Epub 2023 Jul 27.
Incredibly active electrocatalysts comprising earth-abundant materials that operate as effectively as noble metal catalysts are essential for the sustainable generation of hydrogen through water splitting. However, the vast majority of active catalysts are produced via complicated synthetic processes, making scale-up considerably tricky. In this work, a facile strategy is developed to synthesize superhydrophilic Ni/CeO nanoparticles (NPs) integrated into porous carbon (Ni/CeO@C) by a simple two-step synthesis strategy as efficient hydrogen evolution reaction (HER) electrocatalysts in 1.0 M KOH. Benefiting from the electron transport induced by the heterogeneous interface between Ni and CeO NPs and the superhydrophilic structure of the catalyst, the resultant NiCe@C/500 catalysts exhibit a low overpotential of 26 and 184 mV at a current density of 10 and 300 mA cm, respectively, for HER with a small Tafel slope of 62.03 mV dec and robust durability over 300 h, and its overpotential at a high current density is much better than the benchmark commercial Pt/C. Results revealed that the electronic rearrangement between Ni and CeO integrated into porous carbon could effectively regulate the local conductivity and charge density. In addition, the oxygen vacancies and Ni/CeO heterointerface promote water adsorption and hydrogen intermediate dissociation into H molecules, which ultimately accelerate the HER reaction kinetics. Notably, the electrochemical results demonstrate that structural optimization by regulating synthesis temperature and metal concentration could improve the surface features contributing to high electrical conductivity and increase the number of electrochemically active sites on the Ni/CeO@C heterointerface, high crystal purity, and better electrical conductivity, resulting in its exceptional electrocatalytic performance toward the HER. These results indicated that the Ni/CeO@C electrocatalyst has the potential for practical water-splitting applications because of its controlled production strategy and outstanding Pt-like HER performance.
对于通过水分解可持续制氢而言，由储量丰富的材料构成且性能与贵金属催化剂相当的高活性电催化剂至关重要。然而，绝大多数活性催化剂是通过复杂的合成工艺制备的，这使得大规模生产极具挑战性。在这项工作中，我们开发了一种简便的策略，通过简单的两步合成法制备了集成在多孔碳中的超亲水镍/二氧化铈纳米颗粒（NPs）（Ni/CeO@C），作为1.0 M KOH中高效析氢反应（HER）的电催化剂。得益于镍和二氧化铈纳米颗粒之间的异质界面诱导的电子传输以及催化剂的超亲水结构，所得的NiCe@C/500催化剂在电流密度为10和300 mA cm时，HER的过电位分别低至26和184 mV，塔菲尔斜率小至62.03 mV dec，并且具有超过300小时的稳健耐久性，其在高电流密度下的过电位远优于基准商业铂碳。结果表明，集成在多孔碳中的镍和二氧化铈之间的电子重排可以有效调节局部电导率和电荷密度。此外，氧空位和镍/二氧化铈异质界面促进了水的吸附以及氢中间体分解为氢分子，最终加速了HER反应动力学。值得注意的是，电化学结果表明，通过调节合成温度和金属浓度进行结构优化可以改善有助于高电导率的表面特征，并增加Ni/CeO@C异质界面上的电化学活性位点数量、提高晶体纯度和电导率，从而使其对HER具有卓越的电催化性能。这些结果表明，由于其可控的生产策略和类似铂的出色HER性能，Ni/CeO@C电催化剂具有实际水分解应用的潜力。
