Electrosynthesis of formate coupled green hydrogen production on the interface of CuMoO4 nanostructures: A novel electrocatalyst for hybrid water electrolysis system

Developing affordable/efficient catalysts for electrolytic co-production of green hydrogen and value-added products is a prime interest. However, efficient electronic structure engineering of transition metal-based catalysts remains challenging. Herein, we develop high-valent capsule-like copper molybdate (c-CMO) via ultrasonication-assisted strategy. XPS, XANES, KPFM, and DFT studies suggest strong Mo-Cu interaction in c-CMO alters its electronic structure, reduces work function, and lowers ∆G H* . In HER, c-CMO/PNF electrode achieved 130 mV@10 mA/cm² with higher MA and TOF than CO/PNF and MO/PNF electrodes and superior methanol-tolerance than Pt/C. MOR investigations suggest c-CMO/PNF requires 1.39 V@10 mA/cm², 0.239 V lower than OER. Qualitative/quantitative 1 H NMR confirms impressive HCOO − selectivity with ∼96 % Faradaic efficiency. The assembled hybrid AEM water-electrolyzer (HER+MOR) demonstrates 1 A/cm²@2 V (at 60 °C), outperforming HER+OER (2.25 V). The stability test of HAEMWE modeled/predicted using Time-Series-Analysis reveals statistically significant lags, indicating zero autocorrelation. This study emphasizes the development of efficient TMO based catalyst for HAEMWE. • Capsule like-CuMoO 4 (c-CMO) catalyst was developed for HER, OER and MOR. • Mo in Cu matrix enhances the e − transfer and reduces the workfunction (Φ) of c-CMO. • The DFT results suggest that Cu in c-CMO/PNF possess a lower ΔG H* for the HER. • Qualitative/quantitative 1 H NMR confirms impressive HCOO − selectivity with ∼96 % FE. • The stability test of HAEMWE was predicted using Machine learning modelling.