Colossal solar energy conversion and storage studies using photoelectrochemical cells (PECs) have been undertaken in the past four decades; however, how to efficiently utilize solar energy despite the intermittent nature of sunlight still remains a challenge. In this paper, a WO 3 /TiO 2 hybrid photoelectrode was coupled with our newly developed all-vanadium photoelectrochemical cell (PEC) with the aim of implementing photoelectrochemical solar energy conversion and storage. Zeroresistance ammetry (ZRA) and electrochemical impedance spectroscopy (EIS) were employed to study the photoelectrochemical response of this system in the conversion and storage of solar energy both under illumination and in the dark. The preliminary results proved the feasibility of this approach to store/release solar energy, even under dark conditions and showed that hydrogen tungsten bronze was responsible for the storage and release of photogenerated electrons from the semiconductor. The results also indicated an important synergy between electron storage and the all-vanadium electrolytes, which potentially offers great reversibility, high-capacity electron storage, and significant improvement in the photocurrent. To better understand the observed photoelectrochemical and electrochemical impedance behavior of our system, a model that unfolds the WO 3 electron storage mechanism and photogenerated charge carrier pathways in the all-vanadium PEC is proposed.
Au-PtCu core-shell nanoparticles were successfully synthesized via galvanic replacement of Cu by Pt on hollow Au nano-spheres. Characterizations of the nanoparticles were conducted by X-ray diffraction (XRD), transmission electron microscopy (TEM), and electrochemical measurements. Results indicate 2-2.5 times higher specific activity and mass activity of the Au-PtCu catalysts than commercial Pt black and Pt/C in oxygen reduction reaction (ORR), measured in a rotating disk electrode system. Besides, thinner PtCu coating (25 nm thick, deposition time of 20 min) on the hollow Au nano-spheres demonstrated a pronounced CO oxidation peak shift (by 0.13 V) and long-term durability probably due to the unique core-shell structure and strong electronic coupling between the Au core and the PtCu shell.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.