Gan Zhuofan, Cao Jingwen, Chen Zhixu, Qiu Peixi, Bai Jiangyun, Shu Chengyong, Tang Wei
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.
National Innovation Platform (Center) for Industry-Education Integration of Energy Storage Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.
Nanoscale. 2025 Sep 11;17(35):20096-20106. doi: 10.1039/d5nr02238j.
Developing highly active and stable bifunctional electrocatalysts for overall water splitting is critical for sustainable hydrogen production. Herein, the introduction of Co dopants into RuIr alloys resulted in a comprehensive enhancement of both HER and OER activities and stability. Co dopants tuned the electronic structure of Ru/Ir, optimizing the hydrogen binding energy and weakening the OH adsorption ability on Ru/Ir active sites, thereby enhancing HER performance. Co-RuIrO required only a 21.2 mV overpotential to achieve 10 mA cm, with a Tafel slope of 27.9 mV dec and a TOF of 7.18 H per s (at -0.15 V RHE) in the alkaline HER. Additionally, the electrochemical dissolution of Co and the increase in oxygen vacancies promoted the formation of oxygen-deficient Ru/Ir-O species, which are identified as the actual active sites for the OER, thereby initiating a continuous metal site-oxygen vacancy synergistic mechanism (MS-OSM). In this pathway, two OH species nucleophilically attack the adjacent Ru/Ir-O pair and directly couple to form O-O intermediates, thus improving OER activity. Co-RuIrO exhibited an overpotential of 242 mV at 10 mA cm, with a Tafel slope of 41.8 mV dec, and a TOF of 3.23 O per s (at 1.60 V RHE) in alkaline solution. The d-d orbital interactions between Co and RuIr facilitated the electron transfer from Co to Ir and Ru, suppressing particle agglomeration and the dissolution of Ru/Ir species due to severe oxidation, thereby enhancing stability. The constructed Co-RuIrO||Co-RuIrO electrolyzer achieved 10 mA cm at a potential of 1.51 V, demonstrating its potential application in overall water splitting.
开发用于全水分解的高活性和稳定的双功能电催化剂对于可持续制氢至关重要。在此，将钴掺杂剂引入RuIr合金中导致析氢反应（HER）和析氧反应（OER）的活性和稳定性全面增强。钴掺杂剂调节了Ru/Ir的电子结构，优化了氢结合能并削弱了OH在Ru/Ir活性位点上的吸附能力，从而提高了HER性能。在碱性HER中，Co-RuIrO达到10 mA cm只需21.2 mV的过电位，塔菲尔斜率为27.9 mV dec，转换频率为每秒7.18 H（在-0.15 V 可逆氢电极电位下）。此外，钴的电化学溶解和氧空位的增加促进了缺氧Ru/Ir-O物种的形成，这些物种被确定为OER的实际活性位点，从而启动了连续的金属位点-氧空位协同机制（MS-OSM）。在该途径中，两个OH物种亲核攻击相邻的Ru/Ir-O对并直接偶联形成O-O中间体，从而提高OER活性。在碱性溶液中，Co-RuIrO在10 mA cm时的过电位为242 mV，塔菲尔斜率为41.8 mV dec，转换频率为每秒3.23 O（在1.60 V 可逆氢电极电位下）。Co与RuIr之间的d-d轨道相互作用促进了电子从Co转移到Ir和Ru，抑制了由于严重氧化导致的颗粒团聚和Ru/Ir物种的溶解，从而提高了稳定性。构建的Co-RuIrO||Co-RuIrO电解槽在1.51 V的电位下实现了10 mA cm，证明了其在全水分解中的潜在应用。
