Pt single-atomic-site loaded on borate anion-intercalated Co(OH)2 nanoflakes for enhanced hydrogen generation dynamics of NaBH4 hydrolysis

Rational design and preparation of single-atoms (SAs) catalysts with high atom efficiency and anion intercalation offer a promising way to enhancing the catalytic activity of sodium borohydride (NaBH 4 ) hydrolysis. Herein, Pt SAs loaded on borate anion-intercalated Co(OH) 2 nanoflakes (Pt/Co(OH) 2 -B) were synthesized by boron-assisted method and wet impregnation method, achieving a massive metal loading of 9.8 % for the Pt SAs through the oxidation of Co(OH) 2 -B. The optimal catalyst loaded with 6.1 % Pt SAs (Pt M /Co(OH) 2 -B) has a turnover frequency (TOF) of 956.34 mol H2 min - 1 mol Pt -1 , a hydrogen generation rate (HGR) of 9315 mL min - 1 g -1 cat at 30 °C, and a low activation energy of 47.31 kJ mol - 1 for NaBH 4 hydrolysis, outperforming most of the reported noble metal catalysts. The Co element attracts the electrons of Pt SAs, causing Pt SAs to be in an electron-deficient state, which accelerates the adsorption of H 2 O and promotes the hydrolysis rate of NaBH 4 . The remarkable performance is primarily attributed to the synergistic interaction between Pt SAs and α-Co(OH) 2 -B, with a slight shift in the d-band center optimizing the electronic structure of the hydrolysis reaction and reducing the binding energy, thereby achieving exceptional catalytic performance. Density functional theory (DFT) calculations demonstrate that the electronic synergistic interaction between Pt and α-Co(OH) 2 -B reduces the adsorption energy of BH 4 - and H 2 O. The interaction further lowers the energy barrier of B-H bond cleavage as the rate-determining step, thereby accelerating the hydrolysis rate of NaBH 4 . This work provides an innovative approach for the development of green hydrogen production catalysts.