Jihun Oh

Nanostructured Si eliminates several critical problems with Si photocathodes and dramatically improves a photoelectrochemical (PEC) reaction important to water-splitting. Our nanostructured black Si photocathodes improve the H2 production by providing (1) near-ideal anti-reflection that enables the absorption of most incident light and its conversion to photogenerated electrons and (2) extremely high surface area in direct contact with water that reduces the overpotential needed for the PEC hydr

An Si photoelectrode with a nanoporous Au thin film for highly selective and efficient photoelectrochemical (PEC) CO 2 reduction reaction (CO 2 RR) is presented. The nanoporous Au thin film is formed by electrochemical reduction of an anodized Au thin film. The electrochemical treatments of the Au thin film critically improve CO 2 reduction catalytic activity of Au catalysts and exhibit CO Faradaic efficiency of 96% at 480 mV of overpotential. To apply the electrochemical pretreatment of Au film

Development of efficient and selective electrocatalysts is a key challenge to achieve an industry-relevant electrochemical CO2 reduction reaction (CO2RR) to produce commodity chemicals. Here, we report that Au25 clusters with Au-thiolate staple motifs can initiate electrocatalytic reduction of CO2 to CO with nearly zero energy loss and achieve a high CO2RR current density of 540 mA cm–2 in a gas-phase reactor. Electrochemical kinetic investigations revealed that the high CO2RR activity of the Au

conversion rates due to poor mass transport during vigorous electrolysis. Herein, we propose a three-dimensional (3D) hierarchically porous Au comprising interconnected macroporous channels (200-300 nm) and nanopores (∼10 nm) fabricated via proximity-field nanopatterning. The interconnected macropores and nanopores enable efficient mass transport and large active areas, respectively. The roles of each pore network are investigated using reliable 3D nanostructures possessing controlled pore distr

Electrochemical CO 2 reduction is one of the promising ways to convert CO 2 to value-added products such as CO. Many studies have dealt with suppressing the hydrogen evolution reaction (HER) and increasing the CO 2 reduction reaction (CO 2 RR) through modification of the metal surface with additives such as anchoring agent, anion, etc. However, there are only a few studies about modifying the Au surface with additives. We present here a theoretical prediction that the addition of the CN and Cl s

Metal oxides are a promising material for designing highly active and selective catalysts for the electrochemical reduction of carbon dioxide (CO2RR). Here, we designed a Cu/ceria catalyst with high selectivity of methane production at single-atomic Cu active sites. Using this, we report favorable design concepts that push the product selectivity of methane formation by combining detailed structural analysis, density functional theory (DFT), in situ Raman spectroscopy, and electrochemical measur

Converting solar energy by photoelectrochemical water splitting has been regarded as a promising way to resolve the global energy crisis and alleviate environmental pollution. Silicon, which is earth-abundant and has a narrow band gap, is an attractive material for photoelectrochemical water splitting. However, Si-based photoelectrodes suffer from photocorrosion, which leads to instability in electrolytes and high overpotential. Herein, we have fabricated a metal–insulator–semiconductor structur

Electrochemical CO2 conversion offers a promising route for value-added products such as formate, carbon monoxide, and hydrocarbons. As a result of the highly required overpotential for CO2 reduction, researchers have extensively studied the development of catalyst materials in a typical H-type cell, utilizing a dissolved CO2 reactant in the liquid phase. However, the low CO2 solubility in an aqueous solution has critically limited productivity, thereby hindering its practical application. In ef

To exploit the benefits of nanostructuring for enhanced hydrogen evolution reaction (HER), we employed coaxial electrospinning to synthesize single-layered WS2 nanoplates anchored to hollow nitrogen-doped carbon nanofibers (WS2@HNCNFs) as efficient electrocatalysts. For comparison, bulk WS2 powder and single layers of WS2 embedded in nitrogen-doped carbon nanofibers (WS2@NCNFs) were synthesized and electrochemically tested. The distinctive design of the WS2@HNCNFs enables remarkable electrochemi

Ceria (CeO 2 ) is one of the most extensively used rare earth oxides. Recently, it has been used as a support material for metal catalysts for electrochemical energy conversion. However, to date, the nature of metal/CeO 2 interfaces and their impact on electrochemical processes remains unclear. Here, a Cu–CeO 2 nanorod electrochemical CO 2 reduction catalyst is presented. Using operando analysis and computational techniques, it is found that, on the application of a reductive electrochemical pot