South Korean researchers develop new catalyst for hydrogen

In South Korea, in a recent breakthrough, a research team from the Hanyang University ERICA campus in South Korea, has developed a new type of tunable electrocatalyst using B-doped cobalt phosphide (CoP) nanosheets. Their study was published in the journal Small on March 19, 2025. 

The researchers used an innovative strategy to create these materials, using cobalt (Co) based metal-organic frameworks (MOFs). First, they grew Co-MOFs on nickel foam (NF). They then subjected this material to a post-synthesis modification (PSM) reaction with sodium borohydride (NaBH4), resulting in the integration of B. This was followed up by a phosphorization process using different amounts of sodium hypophosphite (NaH2PO2), resulting in the formation of three different samples of B-doped cobalt phosphide nanosheets (B-CoP@NC/NF). 

Experiments revealed that all three samples had a large surface area and a mesoporous structure, key features that improve electrocatalytic activity. As a result, all three samples exhibited excellent OER and HER performance, with the sample made using 0.5 grams of NaH2PO2 (B-CoP0.5@NC/NF) demonstrating the best results. Interestingly, this sample exhibited overpotentials of 248 and 95 mV for OER and HER, respectively, much lower than previously reported electrocatalysts. 

An alkaline electrolyzer developed using the B-CoP0.5@NC/NF electrodes showed a cell potential of just 1.59 V at a current density of 10 mA cm-2, lower than many recent electrolyzers. Additionally, at high current densities above 50 mA cm-2, it even outperformed the state-of-the-art RuO₂/NF(+) and 20% Pt-C/NF(−) electrolyzer, while also demonstrating long-term stability, maintaining its performance for over 100 hours. 

Density functional theory (DFT) calculations supported these findings and clarified the role of B-doping and adjusting P content. Specifically, B-doping and optimal P content led to effective interaction with reaction intermediates, leading to exceptional electrocatalytic performance.