Cobalt-based coordination polymer-derived hexagonal porous cobalt oxide nanoplate as an enhanced catalyst for hydrogen generation from hydrolysis of borohydride

As cobalt is an effective metal for catalyzing hydrolysis of NaBH₄ to produce H₂, Co₃O₄ is a proven catalyst for facilitating NaBH₄ hydrolysis. Since Co₃O₄ can be designed into various morphologies, 2-dimensional plate-like Co₃O₄ can offer large contact surfaces. If the planar surfaces can be even porous, forming porous Co₃O₄ nanoplate (PCNP), this PCNP would be a promising catalyst for HG. Therefore, in this study, a facile approach is developed to fabricate such a PCNP for H₂ generation (HG) from NaBH₄ hydrolysis. Specifically, a cobaltic hexagonal nanoplate-like coordination polymer, which is synthesized via coordinating Co²⁺ with thiocyanuric acid (TA), is adopted as a precursor. Through calcination, Co-TA (CTA) is transformed into hexagonal nanoplate-like Co₃O₄ with pores to become PCNP. More importantly, PCNP showed quite different surficial reactivity and textural properties from commercial Co₃O₄ nanoparticle (Co₃O₄ NP), enabling PCNP to possess a much more superior catalytic activity towards HG from NaBH₄ hydrolysis. PCNP also showed a comparatively low E_a of 35.12 kJ/mol in comparison with the reported catalysts, even precious metal catalysts, and it could be reused up to 10 cycles for HG with stable catalytic activities. These features confirm that PCNP is an advantageous catalyst for HG from NaBH₄ hydrolysis.