Construction of an MXene/MIL Fe-53/ZIF-67 derived bifunctional electrocatalyst for efficient overall water splitting†

Abstract

Research on water splitting is paramount for developing low-carbon alternative energy sources. Nevertheless, creating an efficient, cost-effective, and bifunctional electrocatalyst that facilitates both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) remains an elusive goal. In this work, we report a novel hybrid nanostructured electrocatalyst by combining and pyrolyzing MXene, MIL-53(Fe), and ZIF-67. Comprehensive characterization of the synthesized nanocomposites was conducted using XRD, FESEM, TEM, EDX, and XPS. Notably, among the synthesized electrocatalysts, M3 demonstrated exceptional performance, achieving 10 mA cm⁻² at 237 mV and 50 mA cm⁻² at 292 mV for the OER, and 10 mA cm⁻² at 307 mV and 50 mA cm⁻² at 481 mV for the HER. The Tafel slope values were 64 mV dec⁻¹ for the OER and 185 mV dec⁻¹ for the HER at 10 mA cm⁻². Moreover, M3 exhibited excellent stability, with negligible current density loss over 12 hours, and showed good mass activity of 57.5 and 54.6 A g⁻¹ and TOFs of 1.56 and 2.97 s⁻¹, for the OER and HER, respectively. This study highlights the efficacy of integrating MXene (Ti₃C₂T_x) with MIL-53(Fe) and ZIF-67, creating a potent bifunctional OER and HER electrocatalyst. The synergistic combination enhances electrical conductivity, active site availability, and structural stability, yielding superior performance. The findings of this investigation underscore the importance of strategic design and optimization of bifunctional electrocatalysts for energy conversion applications.