The direct liquid injection chemical vapor deposition (DLI-CVD) method is used to grow pristine and molybdenum (Mo)-doped monoclinic scheelite phase bismuth vanadate (BVO) photoelectrodes. Superior photoelectrochemical (PEC) performance is achieved with ∼200 ± 50 nm thick pristine and 8 at. % Mo-doped BVO films grown at 550 °C. Photocurrent densities as high as ∼1.65 and 3.25 mA/cm2 are obtained for pristine and optimum 8% Mo-doped BVO electrodes, respectively, at 1.23 V vs reversible hydrogen electrode (RHE) under visible light AM 1.5G (100 mW/cm2) in 0.5 M phosphate buffer electrolyte in the presence of 0.1 M Na2SO3 hole scavenger. Somewhat lower photocurrent densities of ∼1.5 and 2.4 mA/cm2 are obtained for pristine and optimum 8% Mo-doped BVO electrodes, respectively, in the absence of Na2SO3. Onset potential values as low as ∼0.1 and 0.3 V vs RHE are achieved with pristine and Mo-doped BVO films for sulfite and water oxidation, respectively. The increased photocurrent density with Mo doping is attributed to enhanced charge carrier density and film conductivity as confirmed by PEC and Mott–Schottky analyses. Because of the dense high quality polycrystalline structure, the DLI-CVD fabricated Mo-doped BVO electrodes exhibit substantial stability under water and sulfite oxidation conditions without any protective layer and/or oxygen evolution cocatalysts. Scanning electrochemical microscopy (SECM) studies confirm the low porosity of Mo:BVO films and production of oxygen in a local area of Mo:BVO electrode under light illumination.

Non precious highly ordered mesoporous carbon (OMC) is of indomitable and perennial catalyst in fuel cells owing to their unique traits and abundant sources. The OMC has been synthesized using KIT-6 sacrificial template and then this removed by three different etching agents, viz, hydrofluoric acid (HF), sodium hydroxide (NaOH) and polyvinylidene fluoride (PVDF). The principle aim of the present work is that to inspect the etched OMCs for oxygen reduction reaction (ORR) activity. In order to understand the effect of etching, we have first studied their fundamental properties. Among three, the HF etched OMC possess comparative surface area (234 m 2 g -1 ), mesoporous sizes (6 nm), large pore volumes (0.13 cm 3 g -1 ) and more accessible defective active sites (I D /I G = 0.90). Hence, the HF etched OMC replica manifest better ORR activity than others in terms of having (0.83 V) onset and (0.71 V) half wave potential, and (2.6 mA/cm 2 at 0.2 V) current density in potassium hydroxide (KOH) electrolyte. From the Nyquist plot, a small semicircle (R ct = 13 Ω cm -2 ) of HF etched OMC substantiates its better ORR activity. A comparative study on etching of OMC using different etching agents could guide to find out a suitable etching agent for modifying the surface properties of OMC.

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Nano-flakes of self-assembled porous pristine and cadmium (Cd) and vanadium (V) doped copper indium disulphide (CuInS2 (CIS)) microspheres are synthesized.