양정장 교수

Solar fuel production, mimicking natural photosynthesis of converting CO2 into useful fuels and storing solar energy as chemical energy, has received great attention in recent years. Practical large-scale fuel production needs a unique device capable of CO2 reduction using only solar energy and water as an electron source. Here we report such a system composed of a gold-decorated triple-layered ZnO@ZnTe@CdTe core-shell nanorod array photocathode and a CH3NH3PbI3 perovskite solar cell in tandem.

Delafossite CuFeO2 is a promising photocathode material for solar hydrogen production, but its performance is low because of poor charge transport properties. When the prepared CuFeO2 electrode is annealed by hybrid microwave annealing (HMA), its photoelectrochemical water reduction activity increases by more than 4 times (-1.3 mA cm(-2) @ 0.4 V-RHE), while the conventional thermal annealing (CTA) improves the performance by only 2 times (-0.62 mA cm(-2) @0.4 V-RHE). The postannealing of the ele

Photoelectrochemical N₂ reduction enables the production of NH₃ under ambient conditions using water as the hydrogen source. Furthermore, by utilizing solar energy, photoelectrochemical N₂ reduction can significantly reduce the energy input required for N₂ reduction. In this study, photoelectrochemical N₂ production was investigated using CuO and Cu₂O photocathodes that are known to be poorly catalytic for water reduction, the maj

Highly efficient tree branch-shaped CuO photocathodes are fabricated using the hybrid microwave annealing process with a silicon susceptor within 10 minutes. The unique hierarchical, one-dimensional structure provides more facile charge transport, larger surface areas, and increased crystallinity and crystal ordering with less defects compared to irregular-shaped CuO prepared by conventional thermal annealing. As a result, the photocathode fabricated with the tree branch-shaped CuO produces an u

As energy-related issues increase significantly, interest in ammonia (NH3) and its potential as a new eco-friendly fuel is increasing substantially. Accordingly, many studies have been conducted on electrochemical nitrogen reduction reaction (ENRR), which can produce ammonia in an environmentally friendly manner using nitrogen molecule (N2) and water (H2O) in mild conditions. However, research is still at a standstill, showing low performances in faradaic efficiency (FE) and NH3 production rate

Abstract An artificial photosynthesis system based on N‐doped ZnTe nanorods decorated with an N‐doped carbon electrocatalyst layer is fabricated via an all‐solution process for the selective conversion of CO 2 to CO. Substitutional N‐doping into the ZnTe lattice decreases the bandgap slightly and improves the charge transfer characteristics, leading to enhanced photoelectrochemical activity. Remarkable N‐doping effects are also demonstrated by the N‐doped carbon layer that promotes selective CO

A zinc telluride (ZnTe) film modified with MoS2 and carbon has been studied as a new photocathode for solar hydrogen production from photoelectrochemical (PEC) water splitting. The modification enhances PEC activity and stability of the photocathode. Thus, the MoS2/C/ZnTe/ZnO electrode exhibits highly improved activity of -1.48 mA cm(-2) at 0 VRHE with a positively shifted onset potential up to 0.3 VRHE relative to bare ZnO/ZnTe electrode (-0.19 mA cm(-2), 0.18 VRHE) under the simulated 1 sun il

Ammonia (NH3) is a clean energy source that can either be directly used as fuel or a hydrogen carrier due to its high energy density and high hydrogen content. The NH3 electro-oxidation reaction (AOR) is the main reaction in both direct NH3 fuel cells and NH3 electrolysis. The AOR is thermodynamically favorable; however, the sluggish kinetics of the reaction can result in issues such as high overpotential, slow reaction rate, deactivation, etc. To overcome this, multiple strategies have been dis

Electrochemical nitrogen reduction (NRR) has attracted much attention as a promising technique to produce ammonia at ambient conditions in an environmentally benign and less energy-consuming manner compared to the current Haber–Bosch process. However, even though much research on the NRR catalysts has been conducted, their low selectivity and reaction rate still hinder the practical application of the NRR process. Among various catalysts, transition metal nitride (TMN)-based catalysts are expect

The formation of a BiSb alloy develops partial charges on the surface, enhancing N 2 adsorption and NH 3 production.

Surface modification strategies that promote electrochemical N₂ reduction on non-noble Bi electrodes in the low overpotential region are developed.

Abstract Ammonia (NH 3 ) has received significant attention due to its increasing demand as a key commodity for industrial chemical production, a green fuel, and a hydrogen (H 2 ) carrier. Electrochemical nitrogen (N 2 ) reduction reaction (ENRR) emerges as the most attractive pathway to produce NH 3 . The process utilizes H 2 O as a proton source under mild temperature and pressure, which can reduce CO 2 emissions and energy input compared to the traditional Haber‐Bosch process. However, ENRR i

3D multi-stacked hyperporous silicon flakes (MHSFs) are prepared via a selective chemical reduction of natural clay minerals bearing MgO negative catalyst layers. The resultant MHSFs are used as a photocatalyst for solar-driven hydrogen evolution and exhibit the highest photocatalytic acitivty (1031 μmol H2 h(-1) g(-1) Si) coupled with a Pt cocatalyst.