Towards optimizing cobalt based metal oxide nanocrystals for hydrogen generation via NaBH4 hydrolysis

•H2 generation, via NaBH4 decomposition, is quantified as a function of Co-based (nano)material deminsion, shape, and composition (i.e. structure-function relationships).•New, reproducible methodologies for unique libraries of cobalt based metal oxide nanomaterials are described.•Hydrogen production rate of 10,367 mL min−1 g−1 with an activation energy of 27.4 kJ  mol-1 was observed for 200 nm wz-CoO-NRs, which is among the lowest reported for CoXOy nanomaterials.