Boosting H₂ generation via NaBH₄ hydrolysis using Co–Zr–B@Co₃O₄ as a novel catalyst: Insights on characterization, catalytic evaluation, kinetics and reusability

In this study, Co₃O₄ supported Co–Zr–B (Co–Zr–B@Co₃O₄) composite, synthesized for the first time to enhance hydrogen (H₂) generation via the catalytic hydrolysis process of sodium borohydride (NaBH₄), is proposed as a next generation catalyst. The successfully fabricated Co–Zr–B@Co₃O₄ catalyst was characterized in detail by XRD, FTIR, BET, SEM, TEM, EDX and XPS techniques. The Zr loading for Co–Zr–B, Co–Zr–B loading for Co–Zr–B@Co₃O₄, NaOH concentration, catalyst amount, NaBH₄ amount and reaction temperature parameters affecting the catalytic hydrolysis process were systematically investigated and optimized. The Co–Zr–B@Co₃O₄ catalyst exhibited superior catalytic performance with values of 26206 mL_H2 g_cat⁻¹ min⁻¹ H₂ generation rate (HGR) and 985 h⁻¹ turnover frequency (TOF) under optimum conditions (1 wt% Zr loading, 5 wt% Co–Zr–B loading, 7 wt% NaOH, 0.03 g catalyst, 0.15 g NaBH₄, 30 °C). The reaction kinetics was evaluated according to the nth order kinetic model and the activation energy was calculated as 50.27 kJ mol⁻¹. After five consecutive reuse cycles, the Co–Zr–B@Co₃O₄ catalyst retained about 48 % and 41 % of the initial HGR and TOF values, respectively, indicating a promising performance in terms of reusability. TEM and FTIR analyses after reuse showed that NaBH₄ and NaBO₂ residues formed on the catalyst surface were effective in the loss of catalytic activity. These results reveal that the Co–Zr–B@Co₃O₄ catalyst is a strong candidate for sustainable and highly efficient H₂ generation applications and highlight its potential to contribute to industrial-scale hydrogen technologies.