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Simultaneous highly efficient production of hydrogen and conversion of biomass into value-added products is meaningful but challenging. Herein, a porous nanospindle composed of carbon-encapsulated MoO2 -FeP heterojunction (MoO2 -FeP@C) is proposed as a robust bifunctional electrocatalyst for hydrogen evolution reaction (HER) and biomass electrooxidation reaction (BEOR). X-ray photoelectron spectroscopy analysis and theoretical calculations confirm the electron transfer from MoO2 to FeP at the interfaces, where electron accumulation on FeP favors the optimization of H2 O and H* absorption energies for HER, whereas hole accumulation on MoO2 is responsible for improving the BEOR activity. Thanks to its interfacial electronic structure, MoO2 -FeP@C exhibits excellent HER activity with an overpotential of 103 mV at 10 mA cm-2 and a Tafel slope of 48 mV dec-1 . Meanwhile, when 5-hydroxymethylfurfural is chosen as the biomass for BEOR, the conversion is almost 100%, and 2,5-furandicarboxylic acid (FDCA) is obtained with the selectivity of 98.6%. The electrolyzer employing MoO2 -FeP@C for cathodic H2 and anodic FDCA production requires only a low voltage of 1.486 V at 10 mA cm-2 and can be powered by a solar cell (output voltage: 1.45 V). Additionally, other BEORs coupled with HER catalyzed by MoO2 -FeP@C also have excellent catalytic performance, implying their good versatility.

An in situ catalytic etching strategy is developed to fabricate holey reduced graphene oxide along with simultaneous coupling with a small-sized Mo2 N-Mo2 C heterojunction (Mo2 N-Mo2 C/HGr). The method includes the first immobilization of H3 PMo12 O40 (PMo12 ) clusters on graphite oxide (GO), followed by calcination in air and NH3 to form Mo2 N-Mo2 C/HGr. PMo12 not only acts as the Mo heterojunction source, but also provides the Mo species that can in situ catalyze the decomposition of adjacent reduced GO to form HGr, while the released gas (CO) and introduced NH3 simultaneously react with the Mo species to form an Mo2 N-Mo2 C heterojunction on HGr. The hybrid exhibits superior activity towards the hydrogen evolution reaction with low onset potentials of 11 mV (0.5 m H2 SO4 ) and 18 mV (1 m KOH) as well as remarkable stability. The activity in alkaline media is also superior to Pt/C at large current densities (>88 mA cm-2 ). The good activity of Mo2 N-Mo2 C/HGr is ascribed to its small size, the heterojunction of Mo2 N-Mo2 C, and the good charge/mass-transfer ability of HGr, as supported by a series of experiments and theoretical calculations.