https://scholar.dgist.ac.kr/handle/20.500.11750/207 2026-11-05T02:35:31Z https://scholar.dgist.ac.kr/handle/20.500.11750/61092 Title: Tailoring the electronic properties of g-C3N4 via D-π-A framework for metal-free photocatalytic CO2 conversion and H2 evolution Author(s): Singh, Rudra P.; Al Marzouqi, Faisal; Hiragond, Chaitanya B.; In, Su-ll; Padma, Lakshmi; Thummala, Sulochana; Murikinati, Mamatha Kumari; Muthukonda Venkatakrishnan, Shankar; Selvaraj, Rengaraj Abstract: Tuning the optical and electronic properties of graphitic carbon nitride (g-C3N4) is an effective strategy for improving solar-light utilization and charge carrier dynamics. Herein, sulfur self-doping was employed to systematically modulate the optoelectronic characteristics of g-C3N4 yielding sulfur-doped carbon nitride (SCN) using thiosemicarbazide as a sulfur source. Subsequently, 2,6-diaminopyridine (DAP) was molecularly incorporated into SCN to construct a donor-it-acceptor (D- it- A) type architecture. DAP incorporation induces an asymmetric electronic environment, promotes charge separation, and suppresses charge-carrier recombination, as indicated by photoluminescence analysis. It also enhances the it-conjugation and broadens the optical absorption range, facilitating improved solar harvesting. The optimized 7 mg DAP-doped SCN (7 DSCN) achieved a CH4 production rate of 0.13686 & micro;mol center dot g- 1 center dot h- 1, through photocatalytic CO2 reduction, approximately 5-fold and 1.5-fold higher than bulk g-C3N4 (BCN) and the SCN respectively. Under outdoor solar light, 7 DSCN delivers an H2 evolution rate of 9 μmol⋅g 1⋅h 1 representing 8.4- and 5.5-fold enhancements over BCN and SCN, respectively. Moreover, 7 DSCN exhibits exceptional photostability, producing 80922 μmol⋅g 1 of H2 accumulated across 13 consecutive days under mid-day peak-hour solar-light irradiation for 4 h per day. This study demonstrates molecular engineering as a promising strategy for developing stable carbon nitride photocatalysts for solar-driven CO2 conversion and H2 production. 2026-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/61086 Title: Advanced carbon architectures for Pt-based oxygen reduction electrocatalysts in polymer electrolyte membrane fuel cells Author(s): Maulana, Muhammad Irfansyah; Yu, Jong-Sung Abstract: Polymer electrolyte membrane fuel cells (PEMFCs) represent a promising platform for clean energy conversion, generating electricity through the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) with high efficiency and near-zero emissions. However, the sluggish ORR at the cathode remains the dominant kinetic limitation hindering the widespread commercialization of PEMFCs. Recent studies suggest that carbon supports play a far more active role than simply providing electrical conductivity, as they can also influence catalytic ORR activity, durability, and mass transport efficiency. In conventional Pt-based catalysts, electrochemical carbon corrosion under harsh fuel cell operating conditions triggers nanoparticle detachment, agglomeration, Ostwald ripening, and dissolution, ultimately causing severe losses in electrochemically active surface area and overall fuel cell performance. This review highlights recent advances in the architectural design of carbon supports for Pt-based ORR electrocatalysts in PEMFCs, focusing on three principal strategies: (i) nitrogen-mediated structural modulation, (ii) nanoparticle-support interfacial anchoring, and (iii) protective carbon encapsulation. Particular emphasis is placed on the understanding of how these engineered carbon architectures mitigate carbon corrosion and enhance Pt stability. The insights discussed herein aim to provide rational design principles for next-generation carbon supports that enable highly active and durable ORR electrocatalysts in PEMFC technologies. 2026-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/61085 Title: Kinetic origin and mitigation of sudden capacity fade in silicon-based lithium-ion batteries Author(s): Jeon, Jiyun; Kang, Junsik; Park, Dae-woon; Lim, Hyun Hee; Kang, Ayeon; Lee, Hyungjin; Hong, Seung-Tae; Lee, Hochun Abstract: Silicon (Si)-based full cells maintain stable cycling at elevated temperatures yet exhibit a sudden capacity fade at room temperature. This temperature-dependent behavior is specific to Si-based full cells and cannot be explained by conventional graphite-based degradation models. This study identifies the origin of the fade mechanism as a Si-intrinsic, kinetics-driven degradation process and proposes a corresponding mitigation strategy. Electrochemical and post-mortem analyses show that intrinsically sluggish Si kinetics at 25 degrees C induce a large overpotential that drives lithium plating and accelerates surface degradation. Guided by this understanding, a formation strategy is introduced to suppress lithium plating onset, which is shown to prevent sudden capacity fade and improve capacity retention from 38% to 85% in NCM/Si cells and from 55% to 93% in NCM/Si-Gr cells. By elucidating the kinetic origin of the sudden capacity fade and establishing formation engineering as an effective and scalable control strategy, this work addresses key challenges in the practical implementation of high-energy Si-based lithium-ion batteries. (c) 2026 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies. 2026-05-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/61082 Title: Oligoethylene Glycol Side-Chain Engineering of Y6-Derived Nonfullerene Acceptors for Thermally Induced Spontaneous Pseudo-Planar Heterojunction Organic Photodetectors Author(s): Park, Se Jeong; Jeong, Sang Young; Eom, Yunji; Kang, Yelim; Choi, Yeonsu; Rhee, Seunghyun; Lee, Bo Ram; Kang, Bong Joo; Jeon, Nam Joong; Shim, Jae Won; Woo, Han Young; Ko, Seo-Jin Abstract: Dark current density (J D) fundamentally limits the noise characteristics and detectivity of organic photodetectors (OPDs), arising primarily from reverse-bias carrier injection and trap-mediated leakage pathways in donor-acceptor (D-A) bulk-heterojunction (BHJ) active layers. Although pseudo-planar heterojunction (p-PHJ) architectures effectively suppress these losses, their implementation often requires complex layer engineering or controlled processing conditions. Here, we report two Y6-derived nonfullerene acceptors (NFAs), YTEG-4F and YTEG-4Cl, bearing hydrophilic oligoethylene glycol (OEG) side chains that induce thermally driven spontaneous vertical phase separation within the D-A BHJ layer. This molecular modification enables p-PHJ formation, suppressing reverse-bias carrier injection and leakage pathways, thereby reducing J D. In contrast to the thermally annealed PM6:Y6 device, which exhibits an increased J D of 6.64 & times; 10-7 A cm-2, the PM6:YTEG-4F and PM6:YTEG-4Cl devices achieve low J Ds of 2.76 & times; 10-9 and 3.24 & times; 10-9 A cm-2, corresponding to approximately 260-fold and 210-fold reductions after thermal annealing, respectively. Consequently, shot-noise-limited detectivities (D sh*) of 1.17 & times; 1013 and 9.74 & times; 1012 Jones are achieved at -0.5 V for PM6:YTEG-4F and PM6:YTEG-4Cl p-PHJ OPDs, respectively. This work demonstrates that OEG side-chain engineering of NFAs provides a broadly applicable molecular strategy for inducing p-PHJ architectures and regulating J D toward high-performance OPDs. 2026-09-30T15:00:00Z