Binder-free electrode materials offer high active material mass loading and usage rate, excellent connectivity between active materials and current collectors, and efficient electron and ion transport inside the electrodes. Herein, we demonstrate a binder-free in situ synthesis of microstructures of CuCo2O4/CuO composites grown on the Ni foam (CCO/NF) by wet chemical methods. Two different morphologies of microspheres (CCO/NF-IPA) and cross-linked microsheets (CCO/NF-DIW) result from solvents of isopropyl alcohol and deionized water, respectively. Using X-ray techniques, the nonstoichiometry of Cu, Co, and O in composites is measured. In the backdrop of the supercapacitor application, even though both electrodes have consistent electrochemical performance, the Co-excess of the CCO/NF-IPA composite has a higher specific capacity (369.6 C g–1 at 1 A g–1) and an extended cyclic performance (98% retention after 5000 cycles) compared to the other. The all-solid-state CCO/NF-IPA//activated carbon (AC) asymmetric supercapacitor (ASC) device with a full operating potential window of 0–1.5 V has exhibited a high specific capacity of 162.6 C g–1 at 1 A g–1. The ASC device retains its initial capacity of 97% over 5000 cycles and renders a notable energy density of 43.7 Wh kg–1 at 752.4 W kg–1 power density.

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CdS based nanocomposites are well reported for photocatalytic hydrogen evolution reactions because of their favorable band edge potentials. The preparation of well dispersed photocatalyst plays an important role in the enhancement of H2 production efficiency. Among all the other morphologies of CdS, nanorods gained considerable attention due to their channeled charge carrying ability and improved surface area. Herein, CdS nanocapsules, which offer short and extensive charge carrier transport and enlarged surface area, were synthesized via the solvothermal method. Poly­(vinyl pyrrolidine) was used as a capping agent for size control and better dispersion. Tungsten oxide nanosheets were synthesized via the hydrothermal route, and CdS nanocapsules were incorporated on the tungsten oxide nanosheets via the wet impregnation method. Photocatalytic hydrogen generation under solar light and simulated solar light irradiations with lactic acid as a sacrificial agent employing the prepared nanocomposite gave impressive and enhanced results, and furthermore the catayst was efficient and stable. The optimized photocatalyst showed a hydrogen production rate of about 146.2 mmol.h–1 .g–1 cat. This is the highest rate reported yet for the combination of CdS and WO3.The Z-scheme heterojunction formation between two different morphologies plays a key role in the enhancement of H2 generation.