Heterostructured Ni3S2-Ni3P/NF as a Bifunctional Catalyst for Overall Urea-Water Electrolysis for Hydrogen Generation
Heterostructured Ni3S2-Ni3P/NF as a Bifunctional Catalyst for Overall Urea-Water Electrolysis for Hydrogen Generation
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异质结构 Ni3S2-Ni3P/NF 作为尿素水电解制氢双功能催化剂
DOI：
10.1021/acsami.1c04325
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发表时间：
2021
影响因子：
9.5
通讯作者：
Chen Yungui
中科院分区：
文献类型：
--
作者：
Liu Jinchao;Wang Yao;Liao Yifei;Wu Chaoling;Yan Yigang;Xie Haijiao;Chen Yungui
尿素氧化反应（UOR）已被提议取代强大的析氧反应（OER），以减少电解水制氢的能耗，因为与 OER 相比，其热力学氧化电位低得多。因此，探索高效稳定的析氢和尿素电氧化双功能催化剂是实现经济高效制氢的关键。在本文中，我们报道了一种通过一步热处理 Ni(OH)2/NF 合成的异质结构硫化物/磷化物催化剂 (Ni3S2–Ni3P/NF)，该催化剂可以同时发生磷化和硫化。所获得的Ni3S2-Ni3P/NF催化剂呈现出平均片层厚度为~100 nm的片状结构，该片状结构由互连的Ni3S2和Ni3P纳米粒子（~20 nm）组成，其间存在大量的Ni3S2-Ni3P可及界面。因此，Ni3S2-Ni3P/NF 在 UOR 和析氢反应 (HER) 方面均表现出优异的性能。对于整个尿素水电解，要实现 10 和 100 mA cm-2 的电流密度，使用该催化剂作为阳极和阴极时，电池电压仅需 1.43 和 1.65 V。此外，该催化剂经过长期测试还保持了相当优异的稳定性，显示出其高效节能制氢的潜力。理论计算结果表明，界面处的Ni原子是HER最有效的催化活性位点，氢吸附自由能最接近热中性，仅为0.16 eV。界面处的自驱动电子转移，使得Ni3S2侧变成给电子而Ni3P侧变成吸电子，可能是UOR活性增强的原因。因此，这项工作展示了一种增强镍基材料催化活性的简单处理方法，以实现高效尿素水电解。
Urea oxidation reaction (UOR) has been proposed to replace the formidable oxygen evolution reaction (OER) to reduce the energy consumption for producing hydrogen from electrolysis of water owing to its much lower thermodynamic oxidation potential compared to that of the OER. Therefore, exploring a highly efficient and stable hydrogen evolution and urea electrooxidation bifunctional catalyst is the key to achieve economical and efficient hydrogen production. In this paper, we report a heterostructured sulfide/phosphide catalyst (Ni3S2–Ni3P/NF) synthesized via one-step thermal treatment of Ni(OH)2/NF, which allows the simultaneous occurrence of phosphorization and sulfuration. The obtained Ni3S2–Ni3P/NF catalyst shows a sheet structure with an average sheet thickness of ∼100 nm, and this sheet is composed of interconnected Ni3S2and Ni3P nanoparticles (∼20 nm), between which there are a large number of accessible interfaces of Ni3S2–Ni3P. Thus, the Ni3S2–Ni3P/NF exhibits superior performance for both UOR and hydrogen evolution reaction (HER). For the overall urea–water electrolysis, to achieve current densities of 10 and 100 mA cm–2, cell voltage of only 1.43 and 1.65 V is required using this catalyst as both the anode and the cathode. Moreover, this catalyst also maintains fairly excellent stability after a long-term testing, indicating its potential for efficient and energy-saving hydrogen production. The theoretical calculation results show that the Ni atoms at the interface are the most efficient catalytically active site for the HER, and the free energy of hydrogen adsorption is closest to thermal neutrality, which is only 0.16 eV. A self-driven electron transfer at the interface, making the Ni3S2sides become electron donating while Ni3P sides become electron withdrawing, may be the reason for the enhancement of the UOR activity. Therefore, this work shows an easy treatment for enhancing the catalytic activity of Ni-based materials to achieve high-efficiency urea–water electrolysis.