Synthesis of 3D Co9S8/GNRs/Ti3C2T –MXene ternary composite toward enhanced oxygen evolution reaction

The incorporation of conductive supports is crucial for achieving superior electrocatalytic performance in transition metal sulfide (TMS) systems. However, the influence of conductive supports with different dimensions remains insufficiently explored. Hereby, quasi–1D graphene nanoribbons (GNRs) and 2D Ti 3 C 2 T x –MXene are for the first time simultaneously introduced to construct a novel 3D Co 9 S 8 /GNRs/Ti 3 C 2 T x ternary composite via a simple annealing process. Systematic characterizations reveal that the GNRs/Ti 3 C 2 T x composite support endows the ternary composite with superior properties, including a unique 3D architecture, improved Co 9 S 8 dispersibility, increased structural defects, and higher conductivity when compared to its binary counterparts. These advantages collectively contribute to significantly enhanced oxygen evolution reaction (OER) performance. Consequently, the Co 9 S 8 /GNRs/Ti 3 C 2 T x catalyst delivers an overpotential of 285 mV at 10 mA cm –2 and a Tafel slope of 78 mV dec –1 , surpassing other comparative catalysts and approaching the performance of commercial RuO 2 catalyst. Additionally, it exhibits remarkable stability, with a negligible overpotential increase of only 2 mV during a 24 h durability test. When employed as an anode catalyst in water–splitting devices, the Co 9 S 8 /GNRs/Ti 3 C 2 T x catalyst requires a low overpotential of 343 mV, manifesting substantial potential for water electrolysis. This work not only reports an excellent OER catalyst, but also offers a valuable strategy for designing high–performance ternary composites for energy–related reactions. A simple annealing process can be used to produce a Co 9 S 8 /GNRs/Ti 3 C 2 T x composite, which shows a unique 3D architecture, promoted dispersibility, increased structural defects and elevated conductivity, thus giving rise to much promoted OER performance. A 3D Co 9 S 8 /GNRs/Ti 3 C 2 T x composite was prepared by a simple annealing process. The ternary composite shows enhanced dispersibility, defects and conductivity. Co 9 S 8 /GNRs/Ti 3 C 2 T x displays excellent performance toward OER. Co 9 S 8 /GNRs/Ti 3 C 2 T x shows great potential for water electrolysis.