0D/1D/2D Co@Co2Mo3O8 nanocomposite constructed by mutual-supported Co2Mo3O8 nanosheet and Co nanoparticle: Synthesis and enhanced hydrolytic dehydrogenation of ammonia borane

• 0D/1D/2D structure is in-situ coupled by Co 2 Mo 3 O 8 nanosheets and Co nanoparticles. • The Co 2 Mo 3 O 8 exists in the form of single-crystal regular hexagonal nanosheets. • 3 mmol H 2 can be completely released within 4 min at 25 °C in the hydrolysis of AB. • The 0D/1D/2D mutual-supported spatial structure contribute to the high performance. • O vacancies also boost adsorption and dissociation process for enhanced activity. Recently, hydrolysis of ammonia borane (AB) is a promising way of producing and employing hydrogen in mild conditions. Nonetheless, the failure to develop inexpensive and high-performance catalyst impedes the further scale hydrogen energy application of AB. Given the fact that ex-situ formed nanocatalysts could be prone to abscission and agglomeration for insufficient dispersion and support, 1D composite microrods with 0D/1D/2D spatial structure constructed by mutual-supported 2D single-crystal Co 2 Mo 3 O 8 nanosheets and 0D Co nanoparticles (denoted as Co@Co 2 Mo 3 O 8 ) have been in-situ synthesized and introduced into the hydrolysis of AB for the first time. Excitingly, the novel Co@Co 2 Mo 3 O 8 exhibits one of the best catalytic performances in the hydrolysis of AB for non-noble metal/metal oxide heterojunction catalysts with TOF value reaching 17.28 m o l H 2 m o l ca t - 1 m i n - 1 at 25 °C, which is 3.95 and 24.0 times that of the single Co 2 Mo 3 O 8 and Co. Meanwhile, two kinds of catalytic components with high intrinsic activity (Co 2 Mo 3 O 8 and Co) and supporting each other in the 0D/1D/2D spatial structure (nanoparticles, microrods, and nanosheets) along with plentiful O vacancies induce the outstanding catalytic activity of Co@Co 2 Mo 3 O 8 . The large-scale controllable preparation method for in-situ fabrication of non-noble metal 0D/1D/2D composite catalysts with high performances would be an accelerator for great potential application for hydrolysis of AB.