Fe-Doped CoNi layered hydrogencarbonate hierarchical Nano-Array assisted growth of ZIF-67 as an efficient OER/UOR bifunctional catalyst reaction for Overall Urea-Water electrolysis

The design of efficient electrocatalysts for OER and UOR is essential for achieving sustainable hydrogen production and enabling simultaneous wastewater treatment. Here, a versatile fabrication method for the in-situ growth of ZIF-67 from hydrocarbonate as a template for three-dimensional hierarchical nano-arrays. This strategy provides an opportunity for controllably tuning the interfacial assembly of MOFs materials on precursor template nanomaterials. The obtained MIM@Fe0.1-CoNi CH/NF exhibited enhanced electrocatalytic performance as an electrocatalytic anode for the OER and UOR. The MIM@Fe0.1-CoNi CH/NF required only 194 mV and 285 mV overpotentials to achieve the current densities of 10 and 100 mA·cm−2 in the electrolyte of 1.0 M KOH, and the overpotentials in the 1.0 M KOH + 0.5 M Urea electrolyte requires only 1.31 V (vs.RHE) to achieve a current density of 10 mA·cm−2. Notably, (+)MIM@Fe0.1-CoNi CH/NF || Pt/C/NF(−) achieves 10 mA·cm−2 in urea-assisted electrolysis at only 1.36 V (vs.RHE). The excellent catalytic performance was attributed to the modification of the CoNi CH/NF template by Fe3+ and 2-MIM, which modulated the Ni2+ and Co2+ electronic structures and optimised the adsorption behaviour of the OER/UOR intermediates. Overall, this work provides a strategy for preparing desirable catalysts for clean energy and wastewater treatment.