Gao Taotao, Qiu Lu, Xie Minghao, Jin Zhaoyu, Li Panpan, Yu Guihua
College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, P. R. China.
Institute for Advanced Study, Chengdu University, Chengdu, 610106, P. R. China.
Mater Horiz. 2023 Oct 2;10(10):4270-4277. doi: 10.1039/d3mh00882g.
The selective two-electron electrochemical oxygen reduction reaction (ORR) for hydrogen peroxide (HO) production is a promising and green alternative method to the current energy-intensive anthraquinone process used in industry. In this study, we develop a single-atom catalyst (CNT-D-O-Fe) by anchoring defect-stabilized and oxygen-coordinated iron atomic sites (Fe-O) onto porous carbon nanotubes using a local etching strategy. Compared to O-doped CNTs with vacancy defects (CNT-D-O) and oxygen-coordinated Fe single-atom site modifying CNTs without a porous structure (CNT-O-Fe), CNT-D-O-Fe exhibits the highest HO selectivity of 94.4% with a kinetic current density of 13.4 mA cm. Fe-O single-atom sites in the catalyst probably contribute to the intrinsic reactivity for the two-electron transfer process while vacancy defects greatly enhance the electrocatalytic stability. Theoretical calculations further support that the coordinated environment and defective moiety in CNT-D-O-Fe could efficiently optimize the adsorption strength of the *OOH intermediate over the Fe single atomic active sites. This contribution sheds light on the potential of defect-stabilized and oxygen-coordinated single-atom metal sites as a promising avenue for the rational design of highly efficient and selective catalysts towards various electrocatalytic reactions.
用于生产过氧化氢（H₂O₂）的选择性双电子电化学氧还原反应（ORR）是一种有前景的绿色替代方法，可替代目前工业上能源密集型的蒽醌法。在本研究中，我们采用局部蚀刻策略，将缺陷稳定且氧配位的铁原子位点（Fe-O）锚定在多孔碳纳米管上，开发了一种单原子催化剂（CNT-D-O-Fe）。与具有空位缺陷的O掺杂碳纳米管（CNT-D-O）和没有多孔结构的氧配位Fe单原子位点修饰的碳纳米管（CNT-O-Fe）相比，CNT-D-O-Fe表现出最高的H₂O₂选择性，为94.4%，动力学电流密度为13.4 mA cm²。催化剂中的Fe-O单原子位点可能有助于双电子转移过程的本征反应性，而空位缺陷极大地提高了电催化稳定性。理论计算进一步支持，CNT-D-O-Fe中的配位环境和缺陷部分可以有效地优化*OOH中间体在Fe单原子活性位点上的吸附强度。这一贡献揭示了缺陷稳定且氧配位的单原子金属位点作为合理设计用于各种电催化反应的高效和选择性催化剂的有前景途径的潜力。
