To develop robust and highly active bifunctional electrocatalysts for electrochemical water splitting in acidic media is still a great challenge for proton exchange membrane (PEM) electrolyzer. Herein, a self-assembled IrCo_x nanorings (NRs) with bracelet-like architecture is fabricated as a bifunctional high-efficient overall water splitting electrocatalyst by a facile, controllable and surfactant-free strategy. The unique nanoring architecture enriches in abundant homointerface and strong synergistic electronic interaction between Ir and Co. The optimized IrCo_0.14 NRs exhibits remarkable electrocatalytic performance with a low overpotential of 16 mV for hydrogen evolution reaction (HER) and 278 mV for oxygen evolution reaction (OER) at 10 mA cm⁻² in 0.1 M HClO₄, respectively, significantly outperforming the commercial Pt/C, Ir/C and reported Ir-based catalysts. As both anode and cathode, a cell voltage of only 1.53 V to reach 10 mA cm⁻² is obtained for overall water splitting and no obvious activity loses after a long-term electrolysis for 14 h. Combined with a PV cell, this catalyst also shows excellent water splitting performance with a solar-to-hydrogen conversion efficiency of 12.8%. This work provides further insights on designing promising and efficient bifunctional electrocatalysts for clean energy electrochemical conversion in the future.

对于质子交换膜（PEM）电解槽而言，开发用于在酸性介质中进行电化学水分解的坚固且高活性的双功能电催化剂仍然是一项巨大的挑战。在此，通过简便，可控且无表面活性剂的策略，将具有手镯状结构的自组装IrCo _x纳米环（NRs）制成双功能高效整体水分解电催化剂。独特的纳米环结构丰富了Ir和Co之间丰富的均相界面和强大的协同电子相互作用。经过优化的IrCo _0.14 NR具有出色的电催化性能，对于氢气析出反应（HER）具有16 mV的低电势，对于氧气析出反应（OER）具有278 mV的低电势）在10 mA cm ^-2时分别在0.1 M HClO _4中溶解，明显优于市售Pt / C，Ir / C和报道的Ir基催化剂。作为阳极和阴极，对于整个水分解而言，仅获得了1.53 V的电池电压即可达到10 mA cm ^-2，并且在长期电解14 h后没有明显的活性损失。与PV电池结合使用时，该催化剂还具有出色的水分解性能，太阳能到氢的转化率为12.8％。这项工作为将来设计用于清洁能源电化学转化的有前途且高效的双功能电催化剂提供了进一步的见解。