Restructuring morphology and surface-electronic-structure of Pt-Co3O4-δ-carbon toward ultra-highly efficient hydrogen production

Although Pt has been verified as the most active catalyst for hydrogen production, it is highly desirable to minimize the usage of Pt while boost the catalytic performance of catalysts considering the low availability and high price of Pt. Herein, we propose a morphology and surface-electronic-structure reconstruction strategy to realize the anchoring of Pt nanoparticles (NPs) on Co3O4-δ-carbon matrix via the co-reduction of Pt precursor and Co3O4-carbon formed by direct pyrolysis of an aerogel composed of cobalt nitrate, chitosan, and urea. The transformation of the porous-network to hierarchically porous structure consisted of Co3O4-δ-carbon nanosheets, deposition of electron-rich Pt NPs, and generation of abundant oxygen-vacancy are facilely achieved through flexible co-reduction of Pt(IV) ions and Co3O4-carbon with ammonia borane (AB). The achieved Pt/Co3O4-δ-UC with an ultralow Pt loading (0.1 wt%) exhibits an ultrahigh activity for hydrolytic AB dehydrogenation with turnover frequencies of 7700 min−1 in aqueous solution at 25 ℃. This catalyst also has a high durability with 71.3% remained activity after ten repetitive cycles. The morphology and surface-electronic-structure reconstruction engaged formation of electron-efficient Pt species could accelerate the oxidative cleavage of O − H bond in H2O and greatly boost the hydrogen generation from hydrolytic AB dehydrogenation. This strategy presented herein offers a new pathway for constructing ultra-highly active supported metal NPs toward hydrogen evolution reaction.