https://scholar.dgist.ac.kr/handle/20.500.11750/17548 Sun, 04 Oct 2026 03:00:51 GMT 2026-10-04T03:00:51Z https://scholar.dgist.ac.kr/handle/20.500.11750/60893 Title: Proton transfer modulation via electrolyte additives for suppressing hydrogen evolution and enhancing C2+ selectivity during acidic CO2 electroreduction Author(s): Kim, Donghwan; Kwon, Woosuck; Lee, Taemin; Seo, Jongwoo; Kim, Heerin; Nam, Dae-Hyun; Kim, Chanyeon Abstract: Suppressing the hydrogen evolution reaction (HER) is a critical challenge for electrochemical reduction of carbon dioxide (CO2RR) in acidic media, where abundant protons drive rapid proton delivery via the Grotthuss mechanism. Although electrolyte additives have been reported to modulate the HER in neutral and alkaline systems, their effects and roles remain largely unexplored under acidic conditions, where proton transport pathways are fundamentally distinct. Here, we identify hydrogen-bond acceptor (HBA) ability as a molecular-level descriptor governing HER suppression in acidic CO2RR. Using glycol-based additives with an identical backbone but varied terminal groups, such as diethylene glycol (DEG), diethylene glycol monomethyl ether (DEGME), and diethylene glycol dimethyl ether (DEGDE), we show that the HBA ability monotonically correlates with HER suppression in acidic media. Additives with high HBA ability accept protons from neighboring water molecules but cannot effectively relay them further, interrupting long-range proton hopping. When we translated additive effects to acidic CO2RR on Cu catalysts, similar HER suppression and concomitant enhancement of the CO2RR were observed. Moreover, the presence of additives also alters selectivity toward C2+ products. In situ Raman spectroscopy confirms that additives with high HBA ability elevate local pH due to regulated proton transfer, and enhance *CO coverage, collectively favoring C-C coupling over C1 formation. The correlation between HBA ability and HER suppression is preserved across various electrolyte conditions. This work establishes HBA ability as a rational design criterion for electrolyte additives that simultaneously suppress the HER and promote C2+ electrosynthesis in acidic media, which can be applicable to other proton-coupled electrochemical systems. Mon, 31 Aug 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60893 2026-08-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60484 Title: Stepwise Activation-Guided Zn Deposition for Ultra-High Capacity in Flowless Zn-Br Batteries Author(s): Han, Jaewoong; Lee, Mingyu; Lee, Hyuntae; Shin, Youyeong; Kim, Suhwan; Shin, Kyungjae; Kim, Chanyeon; Kim, Hee-Tak; Lee, Yong Min; Lee, Hongkyung Abstract: Flowless Zn-bromine batteries (FL-ZBBs) are attracting attention as a route to overcome the inherent system-level limitations of conventional flow batteries. However, the difficulty of achieving high ZnBr2 utilization and ultra-high areal capacity jeopardize practical feasibility: Under practically relevant conditions, Zn-hosting electrodes suffer from top-plating issues and dendrite-triggered "dead" Zn accumulation, which deteriorates reversible Zn plating/stripping. This work presents a stepwise activation (SWA) electrode that guides top-plating-free, bottom-to-top sequential Zn deposition. The SWA architecture is designed by introducing insulating porous membranes physically separating stacked CF layers while electrically linking through controlled partial Zn penetration. Benefiting from SWA-guided Zn deposition, FL-ZBBs can stably retain higher Coulombic and energy efficiencies even at a high current cycling (20 mA cm-2) over 10 000 cycles. For the first time, we demonstrate a stable ultra-high capacity cycling (100 mAh cm-2) of FL-ZBB with SWA electrode by maximizing the ZnBr2 utilization (similar to 33%). This simple, scalable SWA design offers broad applicability, enabling high-capacity operation in flowless batteries and extending to other metal-deposition-limited redox systems. Sat, 28 Feb 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60484 2026-02-28T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60462 Title: Hetero-Solvent Microenvironment for Selective CO2 to Ethanol Electrolysis via Interfacial Water Control Author(s): Kim, Dohun; Lee, Suyun; Jung, Seeun; Kim, Jaemin; Cho, Junsic; Lee, Dong Ki; Back, Seoin; Choi, Chang Hyuck; Kim, Chanyeon Abstract: Electrochemical reduction of carbon dioxide (CO2RR) offers a route for sustainable chemical production using water as a clean proton source. However, water also promotes the competing hydrogen evolution reaction, limiting CO2RR performance. Here we establish interfacial water as a decisive but overlooked design parameter for selective CO2-to-ethanol electrolysis. A hetero-solvent microenvironment confining diglyme (DiG) near the Cu catalyst substantially suppresses HER under both neutral and alkaline conditions, where protons are supplied via water dissociation. In situ infrared absorption spectroscopy and theoretical calculation results reveal that DiG strengthens the hydrogen-bonding network of interfacial water, reducing free-water population prone to dissociation. Concurrently, the modulated water network effectively hinders solvent-mediated hydrogenation that favors ethylene formation, thereby promoting ethanol formation. Because this strategy modulates the microenvironment rather than the catalyst, it readily extends to Cu–Ag bimetallic catalyst. Moreover, confining hetero-solvent within microenvironment rather than in the bulk electrolyte enables high-current operation at low cell voltages, achieving an ethanol partial current density of 184.2mAcm−2 at 3.6V under neutral condition. (Figure presented.) © The Author(s) 2026. Tue, 30 Jun 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60462 2026-06-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59345 Title: Recovering lost performance Author(s): Kwon, Woosuck; Kim, Chanyeon Abstract: Catalysts often transform dynamically during reaction, bringing challenges in terms of changing activity, selectivity, and stability. Research now demonstrates an operation strategy based on in situ catalyst formation and dissolution to recover the performance of catalysts for electrochemical CO2 reduction to methane. Fri, 31 Oct 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59345 2025-10-31T15:00:00Z