Wei Shengjie, Yang Rongyan, Wang Ziyi, Zhang Jijie, Bu Xian-He
School of Materials Science and Engineering, Nankai University, Tianjin, 300350, P. R. China.
Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering of Nankai University, Tianjin, 300350, P. R. China.
Adv Mater. 2024 Aug;36(31):e2404692. doi: 10.1002/adma.202404692. Epub 2024 May 27.
Introducing asymmetric elements and breaking the geometric symmetry of traditional metal-N site for boosting oxygen reduction reaction (ORR) are meaningful and challenging. Herein, the planar chlorination engineering of Fe-N site is first proposed for remarkably improving the ORR activity. The Fe-N/CNCl catalyst with broken symmetry exhibits a half-wave potential (E) of 0.917 V versus RHE, 49 and 72 mV higher than those of traditional Fe-N/CN and commercial 20 wt% Pt/C catalysts. The Fe-N/CNCl catalyst also has excellent stability for 25 000 cycles and good methanol tolerance ability. For Zn-air battery test, the Fe-N/CNCl catalyst has the maximum power density of 228 mW cm and outstanding stability during 150 h charge-discharge test, as the promising substitute of Pt-based catalysts in energy storage and conversion devices. The density functional theory calculation demonstrates that the adjacent C─Cl bond effectively breaks the symmetry of Fe-N site, downward shifts the d-band center of Fe, facilitates the reduction and release of OH, and remarkably lowers the energy barrier of rate-determining step. This work reveals the enormous potential of planar chlorination engineering for boosting the ORR activity of traditional metal-N site by thoroughly breaking their geometric symmetry.
引入不对称元素并打破传统金属 - N 位点的几何对称性以促进氧还原反应（ORR）既具有意义又具有挑战性。在此，首次提出对 Fe - N 位点进行平面氯化工程以显著提高 ORR 活性。具有对称性破缺的 Fe - N/CNCl 催化剂相对于可逆氢电极（RHE）的半波电位（E）为 0.917 V，比传统的 Fe - N/CN 和商业 20 wt% Pt/C 催化剂分别高 49 和 72 mV。Fe - N/CNCl 催化剂还具有出色的 25000 次循环稳定性和良好的甲醇耐受性。对于锌空气电池测试，Fe - N/CNCl 催化剂的最大功率密度为 228 mW/cm²，并且在 150 小时的充放电测试中具有出色的稳定性，有望成为储能和转换装置中 Pt 基催化剂的替代物。密度泛函理论计算表明，相邻的 C─Cl 键有效地打破了 Fe - N 位点的对称性，使 Fe 的 d 带中心下移，促进了 OH 的还原和释放，并显著降低了速率决定步骤的能垒。这项工作揭示了平面氯化工程通过彻底打破传统金属 - N 位点的几何对称性来提高其 ORR 活性的巨大潜力。
