The surface carrier density and hydrogen activation ability are crucial in photocatalytic hydrogen evolution reaction (HER), which can be improved by introducing noble-metal co-catalyst such as Pt into the system. However, the noble-metals suffer from high cost in terms of upscaling, thereby the exploration of low-cost HER co-catalysts is highly demanded. In this work, we report that one-dimensional (1D) metallic MoO2-C nanowire clusters can serve as a co-catalyst in assisting the photocatalytic hydrogen production over 2D g-C3N4. The multiple merits of MoO2-C are demonstrated: (i) noble-metal-free; (ii) highly effective transfer ability of the photogenerated electrons; (iii) high-density adsorption and active sites for hydrogen evolution. As demonstrated in photocatalytic hydrogen production, MoO2-C/2D g-C3N4 exhibits significant enhancement in comparison with pure 2D g-C3N4 semiconductor. The optimal hydrogen evolution rate achieving 1071.0 mu mol g(-1) h(-1), almost 157.5 times higher than that of pure 2D g-C3N4. (C) 2018 Published by Elsevier B.V.