Qiyan Wang

The binding strength between reactant molecules and active sites fundamentally governs reaction selectivity and efficiency, as it determines adsorption energy and activation barriers at the molecular level. However, direct quantification of such molecule‐site binding forces remains challenging, since conventional spectroscopic and microscopic techniques only provide ensemble‐averaged information. Here, we leverage a single‐molecule force imaging strategy that enables quantitative mapping of local binding forces with high spatial resolution under realistic liquid conditions. By covalently tethering functional molecules such as dopamine onto an atomic force microscopy tip, we directly measure site‐specific interaction forces, revealing markedly stronger adhesion at defective sites on MoS ₂ with 218 pN compared to non‐defective regions with 120 pN. Correlating these force signatures with catalytic performance allows quantitative linking of local binding strength to reactivity, yielding reactivity maps at the nanometer scale. This approach extends to other catalysts, including TiO ₂ , providing a broadly applicable route to visualize structure–reactivity relationships at the single‐molecule level.

The binding strength between reactant molecules and active sites fundamentally governs reaction selectivity and efficiency, as it determines adsorption energy and activation barriers at the molecular level. However, direct quantification of such molecule‐site binding forces remains challenging, since conventional spectroscopic and microscopic techniques only provide ensemble‐averaged information. Here, we leverage a single‐molecule force imaging strategy that enables quantitative mapping of local binding forces with high spatial resolution under realistic liquid conditions. By covalently tethering functional molecules such as dopamine onto an atomic force microscopy tip, we directly measure site‐specific interaction forces, revealing markedly stronger adhesion at defective sites on MoS ₂ with 218 pN compared to non‐defective regions with 120 pN. Correlating these force signatures with catalytic performance allows quantitative linking of local binding strength to reactivity, yielding reactivity maps at the nanometer scale. This approach extends to other catalysts, including TiO ₂ , providing a broadly applicable route to visualize structure–reactivity relationships at the single‐molecule level.

Conception de catalyseurs micellaires solides pour une chimie durable: L'épuisement des ressources fossiles et les préoccupations environnementales croissantes encouragent la production de produits chimiques et de carburants durables à partir des ressources de la biomasse et du CO2. L'objectif fondamental de ce projet de recherche concerne la conception d'un nouveau système de catalyseur micellaire à un seul atome. Les catalyseurs sont classiquement classés en homogènes et hétérogènes. Les catalyseurs homogènes offrent une efficacité élevée, liée à une utilisation maximale des métaux et des sites actifs hautement accessibles, et une sélectivité élevée, en raison de la structure similaire du site actif. Cependant, les catalyseurs homogènes souffrent souvent d'une faible stabilité et d'une mauvaise recyclabilité. Au contraire, les catalyseurs hétérogènes présentent une stabilité et une recyclabilité excellentes, mais leur utilisation et sélectivités en métal actif sont généralement faibles. Les catalyseurs mono-atomes (SAC) sont une famille émergente de matériaux qui combinent les meilleurs avantages des catalyseurs homogènes et hétérogènes. Les SAC affichent une utilisation atomique d'environ 100%, une stabilité relativement élevée et une séparation facile du milieu réactionnel. Cependant, il existe plusieurs inconvénients associés à l'utilisation / la synthèse de catalyseurs à un seul atome: la plupart des procédures de synthèse pour les SAC nécessitent l'utilisation de ligands jetables coûteux et d'équipements et de techniques hautement spécialisés qui entravent leur production et leur applicabilité à grande échelle. Un SAC micellaire solide a été développé dans le cadre de ce projet par l'incorporation d'atomes métalliques dans les parois du MCM-41, stabilisé par un tensioactif cétyltriméthylammonium (CTA +). Le procédé est très simple et peu coûteux à synthétiser car il ne nécessite pas l'ajout de ligands coûteux ou de techniques d'atmosphère inerte.

Owing to their high specific surface area, excellent electrical conductivity, and tunable surface functional groups, MXenes show great promise for room-temperature gas sensing. A key limitation, however, arises from the prevalent -F terminations in MXenes prepared by (in-situ) HF etching, which bind gas molecules weakly and result in low sensitivity. To address this, we tailored the surface chemistry using NaOH-assisted hydrothermal etching to synthesize single- or few-layer Ti3C2Tx. This method drastically reduces the -F fraction from 62.11% to 22.68% while elevating the -OH fraction from 12.84% to 63.01%. Consequently, the response to 100 ppm NH3 at 27℃ increases by approximately 30-fold, from 2.09% to 62.55%. Furthermore, we provide the experimental substantiation of proton-conduction and redox mechanisms in MXene-based sensors for NH3 and n-butyl alcohol, with DFT calculations elucidating the pivotal role of the -OH-rich surface in these sensitization mechanisms. This work establishes a clear and definitive correlation between the intrinsic surface functional groups and the gas-sensing performance of MXenes.

Bioelectronic systems integrated with artificial intelligence (AI) are transforming neurochemical diagnostics, enabling intelligent, real-time decoding of brain chemistry. Here, we present an AI-driven biomimetic electrochemical chip with intestine-inspired wrinkled MoS₂ electrodes, enabling dynamic in vivo dopamine monitoring and neuromodulation. This wrinkled structural design promotes efficient molecular capture and alleviates laminar flow limitations, achieving a 23-fold enhancement in dopamine sensitivity over planar electrodes, with detection limits as low as 37 nM in 4.1 μL of biofluid. Moreover, coupled with an AI-assisted decision module, the platform translates neurochemical fluctuations into adaptive modulation, enabling real-time closed-loop neuromodulation. In vivo studies in rats demonstrate autonomous regulation of endogenous dopamine transients, directly linking electrode architecture to functional neural outcomes. This work highlights how bioinspired electrode design, integrated with intelligent signal interpretation, establishes a scalable pathway toward next-generation neurodiagnostics and adaptive bioelectronic interfaces.

Alkaline water electrolysis (ALK) is a promising route for large-scale green hydrogen production, but hydrogen–oxygen mixing during operation poses severe explosion risks, requiring reliable hydrogen-in-oxygen monitoring. Existing sensors suffer from degraded performance under ALK conditions (80–95 °C, 30% KOH) due to water-hydrogen competitive adsorption and alkali corrosion. Here, we report a hydrophobic MoS₂-based semiconductor hydrogen sensor engineered via surface grafting of cetyltrimethylammonium bromide molecules. The resulting protective layer prevents alkali penetration while preserving rapid hydrogen adsorption/desorption. The sensor achieves detection over 0.001–2.5% H₂ with a 3 s response and 50 s recovery and maintains <4.2% sensitivity fluctuation during 10 h operation in simulated harsh environments. This work provides a robust sensing strategy for hydrogen safety monitoring in extreme alkaline electrolysis, with broad implications for safe hydrogen energy deployment.

Real-time monitoring of dopamine (DA) is vital for understanding neurophysiological processes and diagnosing neurological disorders.

Surface-enhanced Raman scattering (SERS) offers significant advantages for single-molecule detection. However, stochastic molecular motion makes it challenging to consistently capture signals from single-molecule binding events, particularly in complex environments. Herein, we propose a novel SERS system via the pore nanoconfinement effect of covalent organic frameworks (COFs) to achieve reliable single-molecule detection. The self-assembled COF thin films on SERS metal substrates (Au/Ag) create a nanogap of 3 nm, allowing electric field enhancement. By precise tuning of the COF shell thickness, a molecular-scale pore volume is formed, effectively trapping individual molecules from molecular aggregates. Furthermore, the strong intermolecular forces within the COF pores significantly enhance the residence time of individual molecules, thereby increasing the probability of detecting single-molecule binding events. This innovative approach ensures consistent and reliable SERS single-molecule detection in complex mixtures, paving the way for advanced applications in biochemical sensing and diagnostics.