Cai Muya, Shi Hao, Zhang Yu, Qu Jiakang, Wang Hongya, Guo Yanyang, Du Kaifa, Li Wei, Deng Bowen, Wang Dihua, Yin Huayi
School of Resource and Environmental Science, Wuhan University, 299 Bayi Road, Wuchang District, Wuhan, 430072, P. R. China.
International Cooperation Base for Sustainable Utilization of Resources and Energy in Hubei Province, Wuhan University, Wuhan, 430072, P. R. China.
Angew Chem Int Ed Engl. 2024 Jun 21;63(26):e202404025. doi: 10.1002/anie.202404025. Epub 2024 May 24.
Reactive metals hydrolysis offers significant advantages for hydrogen storage and production. However, the regeneration of common reactive metals (e.g., Mg, Al, etc.) is energy-intensive and produces unwanted byproducts such as CO and Cl. Herein, we employ Zn as a reactive mediator that can be easily regenerated by electrolysis of ZnO in an alkaline solution with a Faradaic efficiency of >99.9 %. H is produced in the same electrolyte by constructing a Zn-HO hydrolysis battery consisting of a Zn anode and a Raney-Ni cathode to unlock the Zn-HO reaction. The entire two-step water splitting reaction with a net energy efficiency of 70.4 % at 80 °C and 50 mA cm. Additionally, the Zn-HO system can be charged using renewable energy to produce H on demand and runs for 600 cycles only sacrificing 3.76 % energy efficiency. DFT calculations reveal that the desorption of H* on Raney-Ni (-0.30 eV) is closer to zero compared with that on Zn (-0.87 eV), indicating a faster desorption of H* at low overpotential. Further, a 24 Ah electrolyzer is demonstrated to produce H with a net energy efficiency of 65.5 %, which holds promise for its real application.
活性金属水解在储氢和制氢方面具有显著优势。然而，常见活性金属（如镁、铝等）的再生能耗大，且会产生一氧化碳和氯气等有害副产物。在此，我们采用锌作为活性介质，通过在碱性溶液中对氧化锌进行电解，可轻松实现锌的再生，法拉第效率大于99.9%。通过构建由锌阳极和阮内镍阴极组成的锌 - 水解电池，在同一电解液中产生氢气，从而开启锌 - 水解反应。在80°C和50 mA/cm²条件下，整个两步水分解反应的净能量效率为70.4%。此外，锌 - 水解系统可以利用可再生能源充电，按需生产氢气，运行600个循环，能量效率仅损失3.76%。密度泛函理论计算表明，与锌（-0.87 eV）相比，阮内镍上氢原子（H*）的脱附能量（-0.30 eV）更接近零，这表明在低过电位下氢原子的脱附速度更快。此外，一个24 Ah的电解槽被证明产氢的净能量效率为65.5%，这为其实际应用带来了希望。
