A review of the synchronization of emerging nanomaterials and synthesis strategies is presented. Strategic hybridization of emerging nanomaterials modulating the physicochemical properties of the developed heterostructured electrocatalysts for efficient oxygen evolution reactions, as well as the hydrogen evolution reactions is thoroughly discussed, along with the challenges and outlook on the prospect of such nanomaterials for electrocatalytic water splitting.

Hydrogen is considered the “future fuel” due to its zero-carbon emissions, high gravimetric energy density, and sustainability. However, the generation of hydrogen through the splitting of water requires highly efficient bifunctional electrocatalysts to overcome the sluggish kinetics of each half-cell reaction, the oxygen evolution reaction (OER) at the anode and the hydrogen evolution reaction (HER) at the cathode. Various emerging materials, including metal-organic frameworks, 2D materials, single-atom catalysts, high-entropy alloys, perovskites, and MXenes, have shown great potential for OER and HER. However, the synthesis strategies for these materials vary significantly based on their unique physicochemical properties. There has been no proper study on synthesis strategies for each class of the emerging materials or synchronization of the heterostructures formed. The variety in emerging materials and available synthesis routes presents ample opportunity for further exploration of target-oriented materials with unique properties. This review covers recent advancement of emerging materials and their synchronization with existing synthesis strategies for high electrocatalytic activities in water splitting. The review further discusses the challenges and future opportunities for utilizing such emerging materials in water splitting.