Unveiling the Interfacial Species Synergy in Promoting CO2 Tandem Electrocatalysis in Near-Neutral Electrolyte.

The interfacial species-built local environments on Cu surfaces impact the CO2 electroreduction process significantly in producing value-added multicarbon (C2+) products. However, intricate interfacial dynamics leads to a challenge in understanding how these species affect the process. Herein, with ab initio molecular dynamics (AIMD) and finite element method (FEM) simulations, we reveal that the highly concentrated interfacial species, including the *CO, hydroxide, and K+, could synergistically promote the C-C coupling on the one-dimensional (1D) porous hollow structure regulated interfacial environment. The Cu-Ag tandem catalyst was then synthesized with the as-designed structure, exhibiting a high C2+ Faradaic efficiency of 76.0% with a partial current density of 380.0 mA cm-2 in near-neutral electrolytes. Furthermore, in situ Raman spectra validate that the 1D porous structure regulates the concentration of interfacial CO intermediates and ions to increase *CO coverage, local pH value, and ionic field, promoting the CO2-to-C2+ activity. These results provide insights into the design of practical ECR electrocatalysts by regulating interfacial species-induced local environments.

An Aggregation-Induced Fluorescence Probe for Detection H2S and Its Application in Cell Imaging.

Monitoring hydrogen sulfide (H2S) in living organisms is very important because H2S acts as a regulator in many physiological and pathological processes. Upregulation of endogenous H2S concentration has been shown to be closely related to the occurrence and development of tumors, atherosclerosis, neurodegenerative diseases and diabetes. Herin, a novel fluorescent probe HND with aggregation-induced emission was designed. Impressively, HND exhibited a high selectivity, fast response (1 min) and low detection limit (0.61 µM) for H2S in PBS buffer (10 mM, pH = 7.42). Moreover, the reaction mechanism between HND and H2S was conducted by Job's plot, HR-MS, and DFT. In particular, HND was successfully employed to detect H2S in HeLa cells.

Electronic Properties of Defective Janus MoSSe Monolayer.

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) hold great promise in electronics and optoelectronics due to their novel electronic and optical properties. In TMDCs, structural defects are inevitable and might play a decisive role in device performance. In this work, point defects, line vacancies, and 60° grain boundaries (GBs) are explored in 2D Janus MoSSe, a new member to the family of TMDCs, by means of the first-principles calculations. S and Se vacancies are found to be the most favorable point defects, and they tend to aggregate along the zigzag direction to form line vacancies. Comparing with isolated point defects, line vacancies induced in-gap states are more dispersive. In particular, 60° GBs behave as one-dimensional metallic quantum wires, as a consequence of the polar discontinuity. Thus, effectively controlling the formation of defects at nanoscale brings new electronic characteristics, providing new opportunities to broaden the applications of 2D TMDCs.

Free-Standing Nanoarrays with Energetic Electrons and Active Sites for Efficient Plasmon-Driven Ammonia Synthesis.

Direct ammonia (NH3 ) synthesis from water and atmospheric nitrogen using sunlight provides an energy-sustainable and carbon-neutral alternative to the Haber-Bosch process. However, the development of such a route with high performance is impeded by the lack of effective charge transfer and abundant active sites to initiate the nitrogen reduction reaction (NRR). Here, the authors report efficient plasmon-induced photoelectrochemical (PEC) NH3 synthesis on the hierarchical free-standing Au/Kx MoO3 /Mo/Kx MoO3 /Au nanoarrays. Endowed with energetically hot electrons and catalytically active sites, the plasmonic nanoarrays exhibit an efficient PEC NH3 synthesis rate of 9.6 µg cm-2 h-1 under visible light irradiation, which is among the highest PEC NRR systems. This work demonstrates the rationally designed plasmonic nanoarrays for highly efficient NH3 synthesis, which paves a new path for PEC catalytic reactions driven by surface plasmons and future monolithic PEC devices for direct artificial photosynthesis.

Steric effects in the hydrogen evolution reaction based on the TMX4 active center: Fe-BHT as a case study.

In this work, Fe-BHT is identified as the most efficient catalyst for the hydrogen evolution reaction (HER) among the TM-BHTs (TM = Sc, Ti, V, Cr, Mn, Fe, Co, and Ni), with an overpotential as low as 0.09 V. It is found that Fe dz2 orbitals do not participate in the bonding with surrounding S/N atoms in the FeX4 active center but are bonding states for hydrogen adsorption. In accordance with our results, a steric effect determined energy gap acts as an efficient descriptor for the HER activity, which has never been discussed in previous studies. In addition, strain engineering proves the proposed steric effects, which also highlights the importance of the point group symmetry of active centers.

Two-dimensional transition metal borides as high activity and selectivity catalysts for ammonia synthesis.

In comparison to defect/doping induced activity in materials, transition metal borides with exposed metal atoms, large specific surface area, and high active site density show advantages as durable and efficient catalysts for specific electrochemical reactions. In this work, ReB2 for N2 reduction reaction (NRR) for ammonia (NH3) with a record-low limiting potential of UL = -0.05 V and high Faraday efficiency (FE) of 100% is screened out from a new class of TMB2. It is concluded that high pressure/temperature is favorable to N2 adsorption and kinetic barrier minimization; the maximal turnover frequency (TOF) at 700 K and 100 bar is 1.24 × 10-2 per s per site, which is comparable to that of the benchmark Fe3/Al2O3 catalysts, achieving an extremely fast reaction rate. In addition, crystal orbital Hamilton population (COHP) of *N2 reveals the intrinsic origin of N2 activation by analyzing the d-2π* interactions, and integrated COHP could be a quantitative descriptor to describe the N2 activation degree. It is evident that our results not only identify an efficient NRR electrocatalyst in particular, paving the way for sustainable NH3 production, but also explain the chemical and physical origin of the activity, advancing the design principle for catalysts for various reactions in general.

Robust Intrinsic Multiferroicity in a FeHfSe3 Layer.

As a consequence of the mutually exclusive origins of ferroelectricity and magnetism, multiferroic materials with electromagnetic coupling are rare. In this work, stable two-dimensional FeHfSe3 with experimental accessibility is however demonstrated to harbor robust electromagnetic coupling. FeHfSe3 illustrates spontaneous in-plane polarization of 1.29 × 10-10 C/m, and the energy barrier of 116.54 meV ensures easy switching and a high Curie temperature. In addition, semiconducting FeHfSe3 possesses a stable antiferromagnetic ground state with a Néel temperature of approximately 300 K. In the case of applying strain, ferroelectricity and magnetism coexist stably, and uniaxial tensile strain can effectively enhance the ferroelectricity.