Interface-modulated nanojunction and microfluidic platform for photoelectrocatalytic chemicals upgrading

Abstract

Photoelectrocatalytic oxidation provides a technically applicable way for solar-chemical synthesis, but its efficiency and selectivity are moderate. Herein, a microfluidic photoelectrochemical architecture with 3-D microflow channels is constructed by interfacial engineering of defective WO3/TiO2 heterostructures on porous carbon fibers. Kelvin probe force microscopy and photoluminescence imaging visually evidence the charge accumulation sites on the nanojunction. This efficient charge separation contributes to 3-fold enhancement in the yield of glyceraldehyde and 1,3-dihydroxyacetone during glycerol upgrading, together with nearly doubled production of high value-added KA oil and S2O8 2− oxidant through cyclohexane and HSO4 − oxidization, respectively. More importantly, the microfluidic platform with enhanced mass transfer exhibits a typical reaction selectivity of 85%, which is much higher than the conventional planar protocol. Integrating this microfluidic photoanode with an oxygen reduction cathode leads to a self-sustained photocatalytic fuel cell with remarkably high open-circuit voltage (0.9 V) and short-circuit current (1.2 mA cm −2 ).

Simultaneous Phenol Removal and Resource Recovery from Phenolic Wastewater by Electrocatalytic Hydrogenation

“…Carbon fiber cloth was employed as the conductive substrate for the deposition of Ru/TiO 2 catalyst, which can provide massive microflow channels for the mass transfer of reactants (Figure a). , First, TiO 2 nanowires with a diameter of ca. 100 nm and a length of 2 μm were vertically grown onto the seeded carbon skeleton (Figure S1), which showed high electrical conductivity and chemical stability .…”

“…Benefitting from the highly dispersed Ru nanocatalysts loaded on the TiO 2 nanowires, abundant active sites are available for phenol ECH reactions, as can be illustrated in Figure a. Besides, the hierarchical structure of the Ru/TiO 2 electrode provides massive microflow channels for the mass transportation of reactants. , Therefore, both electron and mass transfer can be optimized in the ECH system. As the phenol molecule diffuses to the electrode surface, it is likely to adsorb on the surface of Ru nanoparticle.…”

“…Besides, the hierarchical structure of the Ru/TiO 2 electrode provides massive microflow channels for the mass transportation of reactants. 28,33 Therefore, both electron and mass transfer can be optimized in the ECH system. As the phenol molecule diffuses to the electrode surface, it is likely to adsorb on the surface of Ru nanoparticle.…”

Glycerol Is Converted into Energy and Carbonyl Compounds in a 3D-Printed Microfluidic Fuel Cell: In Situ and In Operando Bi-Modified Pt Anodes

“…28−31 Gu et al used a different 3D-microflow architecture for a photomicrofluidic system that produced current density, glyceraldehyde, and dihydroxyacetone applying WO/TiO 2 anodes in the presence of light. 32 At least to the best of our knowledge, there is no work regarding the production of energy and carbonyl compounds in a μDGFC.…”

Revealing Surface Charge Population on Flake-Like BiVO4 Photocatalysts by Single Particle Imaging Spectroscopies

“…To make this issue clear, a direct probe of crystal-face effects which influence the electrons and holes to different surface reaction sites is highly desirable . Kelvin probe force microscopy (KPFM) is a particular spatially resolved SPV technique, which is capable of studing or directly imaging the electric surface potential distribution at high potential sensitivity (<1 mV) and high spatial resolution (<100 nm) on conducting samples. , With the fast development of a visual imaging technique, KPFM and single-particle fluorescence imaging methods have made this come true. − Additionally, they have been widely used to study charge carrier kinetics and surface reaction processes in a photocatalyst with a built-in electrical field. , BiVO 4 , as an oxygen evolution photocatalyst, has attracted particular interest because of its suitable band gap, good visible-light absorption, and photochemical stability. − Using these techniques and bulk BiVO 4 decahedron crystal as a model, the relationship between the photocatalytic performance of BiVO 4 and the crystal facets was first reported by Li . Currently, most studies about faceted BiVO 4 focus on the spontaneous separation mechanism of charge carriers between different crystal facets.…”