Synergistic effect of phosphorus doping and MoS_(2) co-catalysts on g-C_(3)N_(4) photocatalysts for enhanced solar water splitting

Carbon nitride(g-C_(3)N_(4))is a promising metal-free and visible-light-responsive photocatalyst.However,its photocatalytic efficiency still suffers from high recombination rates of photoinduced charge carriers,slow kinetics of surface redox reactions,and relatively poor light absorption.Herein,a non-noble metal photocatalyst of MoS_(2) nanodots anchored on P-doped g-C_(3)N_(4) via in situ photodeposition was constructed.With the synergetic effect of the P-doping and MoS_(2) co-catalyst,the as-prepared P-doped g-C_(3)N_(4)/MoS_(2) catalyst has achieved efficient photocatalytic overall water splitting with a hydrogen evolution rate of 121.7μmol h−1 g−1.Experimental results and Density functional theory(DFT)simulations indicate that the enhanced photo-absorption capacity originates from the reduced band gaps by P doping.Meanwhile,the MoS_(2) reduces the overpotential of the water oxidation process and improves hydrogen adsorption capability in the hydrogen evolution reaction.This work can pave a new avenue to design and develop noble-metal-free water-splitting photocatalysts for future large-scale applications.

A plastic strain energy method exploration between machined surface integrity evolution and torsion fatigue behaviour of low alloy steel

To explore the evolution mechanism of multistage machining processes and torsional fatigue behaviour based on strain energy for the first time and provide process optimization of axis parts of low alloy steel for service performance,four multistage machining processes were applied to the 45Cr Ni Mo VA steel,including the Rough Turning process(RT),RT+the Finish Turning process(FRT),FRT+the Grinding process(GFRT)and RT+the Finish Turning process on dry cutting condition(FRT0).The result showed that the FRT process’s average low-cycle torsional fatigue life increased by 50%when it evolved from the RT process.The lower surface roughness of R1.3μm caused the total strain energy to increase by 163.8 Pa mm/mm instead of the unchanged strain energy density,and the crack feature evolved from some specific bulges to flat shear plane characteristics.When the GFRT process evolved from the FRT process,its average fatigue life increased by 1.45 times,compared with the RT process.Plastic strain amplitude decreased by 21%,and the strain energy density decreased by 4%due to more considerable compressive residual stress(-249 MPa).Plastic deformation layer depth had a consistent tendency with surface roughness.In this paper,surface integrity evolutions on cyclic characteristics and fatigue behaviour have also been explained.A fatigue life prediction model based on the energy method for machined surface integrity is proposed.