XPS study of a bulk WP hydrodesulfurization catalyst

Tungsten phosphide nanoparticles anchored on ultrathin carbon nanosheets for efficient oxidative desulfurization: Pivotal roles and generation pathways of singlet oxygen

Singlet oxygen (1O2) is an excellent reactive oxygen species for the selective oxidation of organic compounds. Therefore, its application in oxidative desulfurization (ODS) of fuels is theoretically promising, while this has rarely been systematically investigated. Herein, a novel ultrathin carbon nanosheet (CN)-supported tungsten phosphide (WP) catalyst (WP/CN) was devised and employed to activate hydrogen peroxide (H2O2) for the efficient 1O2 generation in ODS. The turnover frequency of WP/CN for the oxidation of dibenzothiophene was as high as 32.7 h-1 at 60 °C, surpassing that of most reported ODS catalysts. More importantly, benefiting from the high selectivity of 1O2, the WP/CN-H2O2 system exhibited exceptional interference resistance and achieved complete ODS of real diesels at a molar ratio of H2O2 to S of 4:1 (the theoretical value is 2:1), outperforming reported ODS systems. The results of experiments and density functional theory calculations demonstrated that the most reasonable reaction pathway for the formation of 1O2 was H2O2→H2O2*→2OH*→O*→2O*→1O2*. The present findings may provide new insights into the development of high-performance and energy-saving ODS processes.

A tungsten phosphide cocatalyst enhanced bismuth tungstate photoanode with the robust built-in electric field towards highly efficient photoelectrochemical water splitting

The use of low-cost and effective cocatalyst is a potential strategy to optimize the effectiveness of photoelectrochemical (PEC) water splitting. In this study, tungsten phosphide (WP) is introduced as a remarkably active cocatalyst to enhance the PEC efficiency of a Bi2WO6 photoanode. The onset potential of Bi2WO6/WP demonstrates a negative shift, while the photocurrent density demonstrates a significant 5.5-fold increase compared to that of unmodified Bi2WO6 at 1.23 VRHE (reversible hydrogen electrode). The loading of WP cocatalyst facilitates the rapid transfer of holes, increasing the range of visible light absorption, the water adsorption ability as well as promoting the separation of photogenerated electrons and holes via the built-in electric field between Bi2WO6 and WP. This study proposes a strategy to hinder the recombination of electron-hole pairs by using WP cocatalyst as a hole capture agent, improve the photoelectric conversion efficiency, and enhance the overall photoelectrochemical properties of Bi2WO6 photoanode.

Sustainable and efficient hydrogen evolution over a noble metal-free WP double modified ZnxCd1-xS photocatalyst driven by visible-light

In terms of energy acquisition, research on the photocatalytic cracking of water to produce hydrogen has become a hub for us to make a transition from theoretical research to practical applications. Charge separations and surface redox reactions of semiconductors are key factors that affect hydrogen production activity. In this study, we used an n-type semiconductor WP as a cocatalyst to modify the solid solution of Zn_xCd_1-xS and found it to have excellent photocatalytic activity under visible light irradiation. Ultraviolet diffuse reflectance spectroscopy showed the red shift of the absorption band of the composite catalyst and the strong absorption of visible light. Under the action of the matching energy band structure, the fluorescence lifetime of the composite catalyst is shortened (2.33 ns) and the electron injection rate is accelerated (K_et = 0.58 × 10⁹ s^-1). Under these favorable conditions, the increased hydrogen production activity of the composite catalyst is finally reflected in the enhanced hydrogen production rate, which reached up to 15 028.6 μmol g^-1 h^-1. In addition, the yield of hydrogen produced by adding a fresh lactic acid catalyst in the fifth cycle after four cycles of testing was greatly improved. Obviously, the addition of WP turns the composite catalyst into a photocatalyst with high efficiency, stability and is a non-noble metal cocatalyst. Finally, through a series of characterization experiments (SEM, TEM, XPS, BET, Mott-Schottky et al.), we proposed the possible mechanism of WP/Zn_xCd_1-xS that efficiently promotes hydrogen production. This provides new understanding for designing an effective cocatalyst modified semiconductor to improve photocatalytic activity.

Photoelectron directional transfer over a g-C3N4/CdS heterojunction modulated with WP for efficient photocatalytic hydrogen evolution

The separation and transfer of photoelectrons is a crucial factor in the process of photocatalysis.

Novel tungsten phosphide embedded nitrogen-doped carbon nanotubes: A portable and renewable monitoring platform for anticancer drug in whole blood

Biosensors based on converting the concentration of analytes in complex samples into single electrochemical signals are attractive candidates as low cost, high-throughput, portable and renewable sensor platforms. Here, we describe a simple but practical analytical device for sensing an anticancer drug in whole blood, using the detection of methotrexate (MTX) as a model system. In this biosensor, a novel carbon-based composite, tungsten phosphide embedded nitrogen-doped carbon nanotubes (WP/N-CNT), was fixed to the electrode surface that supported redox cycling. The electronic transmission channel in nitrogen doped carbon nanotubes (N-CNT) and the synergistic effect of uniform distribution tungsten phosphide (WP) ensured that the electrode materials have outstanding electrical conductivity and catalytic performance. Meanwhile, the surface electronic structure also endows its surprisingly reproducible performance. To demonstrate portable operation for MTX sensing, screen printing electrodes (SPE) was modified with WP/N-CNT. The sensor exhibited low detection limits (45 nM), wide detection range (0.01-540 μM), good selectivity and long-term stability for the determination of MTX. In addition, the technique was successfully applied for the determination of MTX in whole blood.