Harvesting Hydrogen Gas from Air Pollutants with an Unbiased Gas Phase Photoelectrochemical Cell

Abstract

The concept of an all-gas-phase photoelectrochemical (PEC) cell producing hydrogen gas from volatile organic contaminated gas and light is presented. Without applying any external bias, organic contaminants are degraded and hydrogen gas is produced in separate electrode compartments. The system works most efficiently with organic pollutants in inert carrier gas. In the presence of oxygen, the cell performs less efficiently but still significant photocurrents are generated, showing the cell can be run on organic contaminated air. The purpose of this study is to demonstrate new application opportunities of PEC technology and to encourage further advancement toward PEC remediation of air pollution with the attractive feature of simultaneous energy recovery and pollution abatement.

Layer-by-Layer-Stabilized Plasmonic Gold-Silver Nanoparticles on TiO2: Towards Stable Solar Active Photocatalysts

“…The following are available online at www.mdpi.com/article/10.3390/nano11102624/s1, Figure S1: The irradiance spectrum of the used solar simulator, Figure S2: The different AuxAg1−x NP suspensions, Figure S3: DRS spectra for (a) pure anatase species, (b) PC500 species and (c) P25 species, plotting the fraction of reflectance (R%) against the wavelength of the incident light (λ), Figure S4: N2 adsorption (black) and desorption (red) curve, plotting the adsorbed quantity (in cm 3 .g at standard temperature and pressure (STP)) vs. the pressure ratio (P/P0), for a representative (a) pure anatase, (b) PC500, and (c) P25 sample, Figure S5: DRS spectra for P25 + 2 wt % R (black), + 3 wt %. R (red) and + 5 wt % R (blue), plotting the fraction of reflectance (R%) against the wavelength of the incident light (λ).…”

“…Already in the first photocatalysis studies, Fujishima and Honda (1972) pointed out the potential of TiO2 [1]. Its ability to produce reactive charge carriers (both conduction band electrons (e -CB) and valence band holes (h + VB)) under appropriate illumination enabled its use in several application fields, e.g., water splitting [2][3][4][5] and environmental remediation [6]. Additional advantages of TiO2 include its chemical stability, low cost and suitable band edge positions [7].…”

Solid Polymer Electrolyte‐Coated Macroporous Titania Nanotube Photoelectrode for Gas‐Phase Water Splitting

“…The gas‐phase reaction of an all‐solid PEC cell is sustained by a solid–polymer electrolyte membrane, which functions as a proton conductor to replace the aqueous electrolyte . This membrane can separate the H 2 evolution reaction from the O 2 evolution reaction in a similar manner to a protonexchange‐membrane (PEM) electrolyzer .…”

“…PEM‐PEC cells have already been developed by using n‐type semiconductor electrodes composed of materials such as titania (TiO 2 ) nanoparticles. However, these membrane–electrode assemblies (MEAs) exhibit low quantum efficiencies and H 2 production rates …”

Photoelectrochemical Gas–Electrolyte–Solid Phase Boundary for Hydrogen Production From Water Vapor

“…Gas-phase water splitting by all-solid PEC systems has been studied using proton exchange membranes (PEMs) as a solid polymer electrolyte and n-type semiconductor electrodes as a photoanode (Georgieva et al, 2009, 2010; Iwu et al, 2013; Rong et al, 2013; Tsui et al, 2013; Rongé et al, 2014; Stoll et al, 2016, 2017; Verbruggen et al, 2017). PEC water oxidation is induced by photogenerated holes on the photoanode, which is in contact with the membrane, whereas the H 2 evolution reaction occurs on the cathode, which is located on the opposite side of the membrane.…”