The activation of the water molecule (H₂O) serves as the rate-determining step for hydrogen (H 2 ) evolution from the photo-assisted hydrolysis of ammonia borane (NH₃BH₃). Therefore, developing a low-cost efficient catalyst that can expedite the cleavage of O H bonds in H₂O is needed for improving hydrogen production efficiency in practical applications. Here, we prepared a supported non-noble metal catalyst (Co/Mo@MoO 2 –200) with a large number of active sites, comprising ultrathin low-crystalline cobalt (Co) nanosheets grown on amorphous molybdenum oxide (MoO 2 )-coated molybdenum (Mo) nanoparticles (Mo@MoO 2 –200), which serves as a high-performance non-noble metal catalyst to accelerate the activation of O H bonds in H 2 O. Notably, visible light irradiation facilitates the formation of ultrathin Co nanosheets by inducing the localized surface plasmon resonance of MoO 2 , as verified by transmission electron microscopy (TEM) images. Moreover, X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopy (XPS) spectra confirm the electron transfer from Co nanosheets to O sites in Mo@MoO 2 –200, establishing robust interfaces. Co/Mo@MoO 2 –200 exhibits high catalytic performance with the turnover frequency (TOF) value of 110.8 min −1 under visible light irradiation, which is greater than that of Co/Mo by 1.21 times and most of the reported Co-based catalysts. DFT calculations reveal that the Mo@MoO 2 –200 support in the catalyst can promote the Co-adsorption of NH 3 BH 3 and H 2 O, while facilitating H 2 desorption. Particularly, the Co/Mo@MoO 2 –200 can significantly decrease the activation energy barrier of the O H bond in H 2 O, compared with pristine Co and Mo@MoO 2 –200. This paper presents a flexible catalyst design strategy for NH 3 BH 3 hydrolysis and other H 2 O-associated catalytic reactions.
Juan Sun,Yihui Zou,Penghui Ren,Peng Wang,Zhiyan Zhu,Can Cui
Perovskite solar cells (PSCs) in an n-i-p structure function well in large part due to the exceptional electrical conductivity and surface morphology of the SnO2-based transport layer (ETL). Here, we report a strategy to enhance the conductivity and tailor the surface morphology of the SnO2 ETL by incorporating molybdic acid (H2MoO4), forming a modified SnO2:H2MoO4 ETL. The incorporation of Mo6+ ions substitutes Sn4+ sites and inhibits the formation of oxygen vacancies (VO), resulting in an upshifted Fermi level and enhanced electron transport efficiency of SnO2. The H+ ions react with surface hydroxyl (−OH) defects through electrostatic interactions, suppressing surface defect generation and reducing nonradiative recombination. In addition, the in situ-formed amorphous MoO3 in the SnO2 matrix contributes to a denser and more uniform ETL. Consequently, the H2MoO4-modified PSCs achieve a champion PCE of 24.27%, marking a notable 9.5% boost compared to the control devices (22.17%), along with significantly enhanced long-term stability.
Litao Han,Hong Liu,Chen Lu,Yuanzhi Wei,Fanjun Kong
Molybdenum trioxide (MoO 3 ) possesses unique layered structure with high theoretical capacity and good environmental friendliness, which has been widely investigated as a potential anode material. Herein, MoO 3 nanosheets anchored in N-doped reduced graphene oxide (MoO 3 /NG) composite was constructed and prepared through hydrothermal reaction and post-calcination. The introduction of NG matrix can enhance the electronic conductivity and accelerate reaction kinetics of the MoO 3 , and solve the problem of severe capacity decay caused by its volume changes. MoO 3 /NG composite can deliver superior cycling performance (900.2 mAh g −1 at 0.2 Ag −1 after 100 cycles and 407.5 mAh g −1 at 10.0 Ag −1 after 500 cycles) and fast reaction kinetics with high diffusion coefficients and low charge transfer resistances. Moreover, the excellent electrochemical performance of the full battery lays a solid foundation for subsequent commercial application research.
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