Nanoporous PtCo/Co 3 O 4 composites with high catalytic activities toward hydrolytic dehydrogenation of ammonia borane.

The design and fabrication of highly active and durable catalysts for the ammonia borane (AB) hydrolysis has been one of significant issues in the application of green and economic hydrogen energy. Nanoporous (NP) PtCo/Co3 O4 composites are straightforwardly fabricated by selectively etching Al atoms followed by removing Co atoms from the PtCoAl precursor alloy. By controlling the second-step dealloying, the NP-PtCo/Co3 O4 composites evolved into pure nanoporous structure with Co3 O4 nanosheets on the surface gradually disappeared as well different Pt/Co ratios resulted. Compared with NP-Pt and pure Co3 O4 catalysts, the NP-PtCo/Co3 O4 composites with different Pt/Co ratios exhibit markedly enhanced catalytic activity for the hydrolysis of AB. NP-Pt40 Co60 composite with some Co3 O4 nanosheets anchored on the surface shows the higher catalytic activity compared to other several samples with different Pt contents, exhibiting a high initial turnover frequency of 131mol H2 min-1 (mol Pt)-1 . Meanwhile, the recyclability tests indicate that NP-Pt40 Co60 composite retained 65% of the initial catalytic activity after the fifth run of hydrolysis. Therefore, the high catalytic activity and good durability render the as-made composite as a powerful catalyst candidate for the hydrolytic dehydrogenation of AB in the practical applications.