School of Chemistry and Chemical Engineering, Shanxi Key Laboratory of High Performance Battery Materials and Devices, North University of China, Taiyuan 030051, People's Republic of China.
School of Environment and Safety Engineering, North University of China, Taiyuan 030051, People's Republic of China.
Dalton Trans. 2023 Jun 27;52(25):8811-8817. doi: 10.1039/d3dt01162c.
The development of efficient and stable non-precious-metal-based electrocatalysts is essential for practical water splitting applications. The electrolysis of water for hydrogen production is a green and efficient method, while urea electrolysis can improve energy conversion efficiency. In this paper, W-NiS/NiS catalysts with heterogeneous structures were synthesized a one-step hydrothermal method using a W-doping-induced phase transition strategy. The doping of W modulates the morphology of the catalyst, which can form uniform nanorod arrays and improve the activity of the electrocatalyst. In an alkaline solution of 1 M KOH and 0.5 M urea, W-NiS/NiS requires a potential of only 1.309 V to achieve a current density of 10 mA cm. An electrolyzer containing urea with W-NiS/NiS as both the cathode and anode can drive a current density of 10 mA cm with a potential of only 1.569 V and has relatively good stability after testing for 20 h. Experimental results show that the improvement in the catalytic activity is due to the rapid charge transfer, exposure of more active sites and better conductivity. Density functional theory calculations show that the W-NiS material exhibits higher urea adsorption energy, indicating that urea is preferentially adsorbed on its surface. The NiS material shows more state density near the Fermi level, indicating that the introduction of this material enhances the conductivity of the W-NiS/NiS material. The synergistic catalysis of the two materials promoted the improvement of the catalytic activity. This work provides new ideas for the development of highly efficient and stable catalysts by means of doping and interface construction.
开发高效稳定的非贵金属基电催化剂对于实际的水分解应用至关重要。水的电解制氢是一种绿色高效的方法，而尿素电解可以提高能量转换效率。本文采用一步水热法，通过 W 掺杂诱导的相变策略，合成了具有异质结构的 W-NiS/NiS 催化剂。W 的掺杂调节了催化剂的形态，可以形成均匀的纳米棒阵列，提高电催化剂的活性。在 1 M KOH 和 0.5 M 尿素的碱性溶液中，W-NiS/NiS 仅需 1.309 V 的电位即可达到 10 mA cm 的电流密度。含有 W-NiS/NiS 的尿素电解槽作为阴极和阳极，仅需 1.569 V 的电位即可驱动 10 mA cm 的电流密度，经过 20 小时测试后具有相对较好的稳定性。实验结果表明，催化活性的提高是由于快速电荷转移、暴露更多的活性位点和更好的导电性。密度泛函理论计算表明，W-NiS 材料具有更高的尿素吸附能，表明尿素优先吸附在其表面。NiS 材料在费米能级附近表现出更多的态密度，表明引入这种材料增强了 W-NiS/NiS 材料的导电性。两种材料的协同催化促进了催化活性的提高。这项工作为通过掺杂和界面构建开发高效稳定的催化剂提供了新的思路。
