Linke Julia, Rohrbach Thomas, Clark Adam Hugh, Borca Camelia, Huthwelker Thomas, Buchauer Fabian Luca, Kraglund Mikkel Rykær, Chatzichristodoulou Christodoulos, Meade Eibhlin, Guehl Julie, Wojtas Mateusz, Ranocchiari Marco, Schmidt Thomas Justus, Fabbri Emiliana
PSI Center for Energy and Environmental Sciences 5232 Villigen PSI Switzerland
PSI Center for Photon Science 5232 Villigen PSI Switzerland.
EES Catal. 2025 Feb 4;3(3):505-514. doi: 10.1039/d4ey00250d. eCollection 2025 May 8.
The performance of Ni-based oxygen evolution reaction (OER) electrocatalysts is enhanced upon Fe incorporation into the structure during the synthesis process or electrochemical Fe uptake from the electrolyte. In light of the promising potential of metal-organic framework (MOF) electrocatalysts for water splitting, Ni-MOF-74 is used as a model catalyst to study the effect of Fe incorporation from KOH electrolyte on the electrocatalyst's OER activity and stability. The insights obtained from X-ray diffraction and operando X-ray absorption spectroscopy characterization of Ni-MOF-74 and an amorphous Ni metal organic compound (Ni-MOC*) reveal that Fe uptake enhances OER by two processes: higher Ni oxidation states and enhanced flexibility of both, the electronic state and the local structure, when cycling the potential below and above the OER onset. To demonstrate the impressive OER activity and stability in Fe containing KOH, an Ni-MOC* anode was implemented in an anion exchange membrane water electrolyzer (AEM-WE) with 3 ppm Fe containing 1 M KOH electrolyte resulting in an outstanding cell voltage of 1.7 V (at an anode potential of 1.51 V) at 60 °C and 0.5 A cm exceeding 130 h of stable continuous operation.
在合成过程中将铁掺入结构中或通过从电解质中进行电化学铁摄取时，镍基析氧反应（OER）电催化剂的性能会得到增强。鉴于金属有机框架（MOF）电催化剂在水分解方面具有广阔的潜力，使用Ni-MOF-74作为模型催化剂来研究从KOH电解质中掺入铁对电催化剂的OER活性和稳定性的影响。通过对Ni-MOF-74和非晶态镍金属有机化合物（Ni-MOC*）进行X射线衍射和原位X射线吸收光谱表征获得的见解表明，铁摄取通过两个过程增强OER：当在OER起始电位上下循环时，更高的镍氧化态以及电子态和局部结构的灵活性增强。为了证明在含Fe的KOH中具有令人印象深刻的OER活性和稳定性，在阴离子交换膜水电解槽（AEM-WE）中使用了Ni-MOC*阳极，该电解槽使用含3 ppm Fe的1 M KOH电解质，在60°C和0.5 A cm的条件下，阳极电位为1.51 V时，电池电压达到1.7 V，实现了超过130小时的稳定连续运行。
