Precise Design and Modification Engineering of Single-Atom Catalytic Materials for Oxygen Reduction.

Due to their unique electronic and structural properties, single-atom catalytic materials (SACMs) hold great promise for the oxygen reduction reaction (ORR). Coordinating environmental and engineering strategies is the key to improving the ORR performance of SACMs. This review summarizes the latest research progress and breakthroughs of SACMs in the field of ORR catalysis. First, the research progress on the catalytic mechanism of SACMs acting on ORR is reviewed, including the latest research results on the origin of SACMs activity and the analysis of pre-adsorption mechanism. The study of the pre-adsorption mechanism is an important breakthrough direction to explore the origin of the high activity of SACMs and the practical and theoretical understanding of the catalytic process. Precise coordination environment modification, including in-plane, axial, and adjacent site modifications, can enhance the intrinsic catalytic activity of SACMs and promote the ORR process. Additionally, several engineering strategies are discussed, including multiple SACMs, high loading, and atomic site confinement. Multiple SACMs synergistically enhance catalytic activity and selectivity, while high loading can provide more active sites for catalytic reactions. Overall, this review provides important insights into the design of advanced catalysts for ORR.

A 3D-printed phantom for quality-controlled reproducibility measurements of arterial spin labeled perfusion.

PURPOSE: To develop a portable MR perfusion phantom for quality-controlled assessment and reproducibility of arterial spin labeled (ASL) perfusion measurement. METHODS: A 3D-printed perfusion phantom was developed that mimics the branching of arterial vessels, capillaries, and a chamber containing cellulose sponge representing tissue characteristics. A peristaltic pump circulated distilled water through the phantom, and was first evaluated at 300, 400, and 500 mL/min. Longitudinal reproducibility of perfusion was performed using 2D pseudo-continuous ASL at 20 post-label delays (PLDs, ranging between 0.2 and 7.8 s at 0.4-s intervals) over a period of 16 weeks, with three repetitions each week. Multi-PLD data were fitted into a general kinetic model for perfusion quantification (f) and arterial transit time (ATT). Intraclass correlation coefficient was used to assess intersession reproducibility. RESULTS: MR perfusion signals acquired in the 3D-printed perfusion phantom agreed well with the experimental conditions, with progressively increasing signal intensities and decreasing ATT for pump flow rates from 300 to 500 mL/min. The perfusion signal at 400 mL/min and the general kinetic model-derived f and ATT maps were similar across all PLDs for both intrasession and intersession reproducibility. Across all 48 experimental time points, the average f was 75.55 ± 3.83 × 10-3 mL/mL/s, the corresponding ATT was 2.10 ± 0.20 s, and the T1 was 1.84 ± 0.102 s. Intraclass correlation coefficient was 0.92 (95% confidence interval 0.83-0.97) for f, 0.96 (0.91-0.99) for ATT, and 0.94 (0.88-0.98) for T1 , demonstrating excellent reproducibility. CONCLUSION: A simple, portable 3D-printed perfusion phantom with excellent reproducibility of 2D pseudo-continuous ASL measurements was demonstrated that can serve for quality-controlled and reliable measurements of ASL perfusion.

Hydrogen Nanobubbles Generated In Situ from Nanoscale Zerovalent Iron with Water to Further Enhance Selenite Sequestration.

Gas nanobubbles used for water treatment and recovery give rise to great concern for their unique advantages of less byproducts, higher efficiency, and environmental friendliness. Nanoscale zerovalent iron (nZVI), which has also been widely explored in the field of environmental remediation, can generate gas hydrogen by direct reaction with water. Whether nanoscale hydrogen bubbles can be produced to enhance the pollution removal of the nZVI system is one significant concern involved. Herein, we report direct observations of in situ generation of hydrogen nanobubbles (HNBs) from nZVI in water. More importantly, the formed HNBs can enhance indeed the reduction of Se(IV) beyond the chemical reduction ascribed to Fe(0), especially in the anaerobic environment. The possible mechanism is that HNBs enhance the reducibility of the system and promote electron transport in the solution. This study demonstrates a unique function of HNBs combined with nZVI for the pollutant removal and a new approach for in situ HNB generation for potential applications in the fields of in situ remediation agriculture, biotechnology, medical treatment, health, etc.

Characteristics of Gaseous Elemental Mercury in a Suburban Area of Shanghai, China.

To clarify gaseous elemental mercury (GEM) in suburban megacities in the Yangtze River Delta region, China, we observed GEM concentrations from December 2019 to November 2020 in Wujing town, a suburban area of Shanghai. The annual mean GEM concentration was 1.44 ± 0.88 ng m-3. Compared with the historical monitoring data of GEM in Shanghai over the past 10 years, the concentration of GEM showed a decreasing trend. The monthly mean concentrations of GEM showed clear seasonal variation, with higher values in the spring and winter. In spring and winter, typical Hg pollution events were observed, which could be mostly associated with increased local anthropogenic activity and temperature inversion. The results of the correlation analysis of the daily mean GEM concentrations with the AQI and backward trajectory calculations indicate that mercury pollution at monitoring sites can be affected by local, regional and interregional influences.

Fe, N-Inducing Interfacial Electron Redistribution in NiCo Spinel on Biomass-Derived Carbon for Bi-functional Oxygen Conversion.

Herein, an interfacial electron redistribution is proposed to boost the activity of carbon-supported spinel NiCo2O4 catalyst toward oxygen conversion via Fe, N-doping strategy. Fe-doping into octahedron induces a redistribution of electrons between Co and Ni atoms on NiCo1.8Fe0.2O4@N-carbon. The increased electron density of Co promotes the coordination of water to Co sites and further dissociation. The generation of proton from water improves the overall activity for the oxygen reduction reaction (ORR). The increased electron density of Ni facilitates the generation of oxygen vacancies. The Ni-VO-Fe structure accelerates the deprotonation of *OOH to improve the activity toward oxygen evolution reaction (OER). N-doping modulates the electron density of carbon to form active sites for the adsorption and protonation of oxygen species. Fir wood-derived carbon endows catalyst with an integral structure to enable outstanding electrocatalytic performance. The NiCo1.8Fe0.2O4@N-carbon express high half-wave potential up to 0.86 V in ORR and low overpotential of 270 mV at 10 mA cm-2 in OER. The zinc-air batteries (ZABs) assembled with the as-prepared catalyst achieve long-term cycle stability (over 2000 cycles) with peak power density (180 mWcm-2). Fe, N-doping strategy drives the catalysis of biomass-derived carbon-based catalysts to the highest level for the oxygen conversion in ZABs.

Two-dimensional Cu Plates with Steady Fluid Fields for High-rate Nitrate Electroreduction to Ammonia and Efficient Zn-Nitrate Batteries.

Nitrate electroreduction reaction (eNO3 -RR) to ammonia (NH3) provides a promising strategy for nitrogen utilization, while achieving high selectivity and durability at an industrial scale has remained challenging. Herein, we demonstrated that the performance of eNO3 -RR could be significantly boosted by introducing two-dimensional Cu plates as electrocatalysts and eliminating the general carrier gas to construct a steady fluid field. The developed eNO3 -RR setup provided superior NH3 Faradaic efficiency (FE) of 99 %, exceptional long-term electrolysis for 120 h at 200 mA cm-2, and a record-high yield rate of 3.14 mmol cm-2 h-1. Furthermore, the proposed strategy was successfully extended to the Zn-nitrate battery system, providing a power density of 12.09 mW cm-2 and NH3 FE of 85.4 %, outperforming the state-of-the-art eNO3 -RR catalysts. Coupled with the COMSOL multiphysics simulations and in situ infrared spectroscopy, the main contributor for the high-efficiency NH3 production could be the steady fluid field to timely rejuvenate the electrocatalyst surface during the electrocatalysis.

Co-Adjusting d-Band Center of Fe to Accelerate Proton Coupling for Efficient Oxygen Electrocatalysis.

The problem in d-band center modulation of transition metal-based catalysts for the rate-determining steps of oxygen conversion is an obstacle to boost the electrocatalytic activity by accelerating proton coupling. Herein, the Co doping to FeP is adopted to modify the d-band center of Fe. Optimized Fe sites accelerate the proton coupling of oxygen reduction reaction (ORR) on N-doped wood-derived carbon through promoting water dissociation. In situ generated Fe sites optimize the adsorption of oxygen-related intermediates of oxygen evolution reaction (OER) on CoFeP NPs. Superior catalytic activity toward ORR (half-wave potential of 0.88 V) and OER (overpotential of 300 mV at 10 mA cm-2 ) express an unprecedented level in carbon-based transition metal-phosphide catalysts. The liquid zinc-air battery presents an outstanding cycling stability of 800 h (2400 cycles). This research offers a newfangled perception on designing highly efficient carbon-based bifunctional catalysts for ORR and OER.

Recent advances on low-Co and Co-free high entropy layered oxide cathodes for lithium-ion batteries.

As the price of the precious metal cobalt continues to rise, there is an urgent need for a cobalt-free or low-cobalt electrode material to reduce the cost of lithium-ion batteries, which are widely used commercially, while maintaining their performance as much as possible. With the introduction of the new concept of high entropy (HE) materials into the battery field, low cobalt and cobalt free HE novel lithium-ion batteries have attracted great attention. It possesses important research value to use HE materials to reduce the use of cobalt metal in electrode materials. In this perspective, the comparison between the new cathode materials of low cobalt and cobalt-free HE lithium-ion battery and traditional cathode materials and the latest progress in maintaining structural stability and conductivity are introduced. It is believed that low cobalt and cobalt-free and HE layered oxides can be used to replace the function of cobalt in the cathode materials of lithium-ion batteries. Finally, the future research directions and the synthesis method of HE cathode materials for lithium-ion batteries are also discussed.

A short peptide encoded by long non-coding RNA small nucleolar RNA host gene 6 promotes cell migration and epithelial-mesenchymal transition by activating transforming growth factor-beta/SMAD signaling pathway in human endometrial cells.

BACKGROUND: Endometrial dysfunction is closely correlated with the development of multiple severe gynecological disorders including intrauterine adhesion. Accumulating evidence supports that some long non-coding RNAs (lncRNAs) have peptide-coding potential. In this text, the peptide-coding ability of lncRNA SNHG6 was examined. Also, the effects of an SNHG6-encoded peptide on the viability and migration of human endometrial stromal cells (hESCs) and human endometrial epithelial cells (hEECs) and related molecular mechanisms were explored. METHODS: The peptide-encoding potential of SNHG6 was predicted by FuncPEP and getorf databases and validated by western blot assay. Cell viability was tested by cell counting kit-8 assay. Cell migratory ability was examined by wound healing and transwell migration assays. Protein levels of genes were measured by western blot assay. RESULTS: Prediction analysis suggested that SNHG6 had the potential peptide-coding ability and multiple open-reading frames (ORFs). Western blot validated that SNHG6 ORF#1 and ORF#2 could translate into short peptides. SNHG6 ORF#2 overexpression facilitated cell migration and epithelial-mesenchymal transition (EMT) in hESCs and hEECs, while these effects were abrogated by transforming growth factor-beta (TGF-ß)/SMAD signaling inhibitor GW788388. Moreover, GW788388 inhibited the increase of p-SMAD2 and p-SMAD3 levels induced by SNHG6 ORF#2 in hESCs. SNHG6 ORF#2-encoded peptide did not influence endometrial stromal and epithelial cell viability. CONCLUSIONS: LncRNA SNHG6 ORF#1 and ORF#2 could translate into small peptides and SNHG6 ORF#2 overexpression promoted cell migration and EMT by activating the TGF-ß/SMAD pathway in hESCs and hEECs, suggesting the potential roles of SNHG6-encoded peptides in the development of endometrial stromal and epithelial cells and related gynecological diseases.

Changes in Academic Self-efficacy and Value and Crossover of Burnout Among Adolescent Students: A Two-wave Longitudinal Study.

Previous research has identified the crossover of burnout among spouses or colleagues in workplaces, but little is known about how burnout crosses over from one student to another. This two-wave longitudinal study examined the mediating effects of changes in academic self-efficacy and value in the crossover of burnout among adolescent students based on the Expectancy-Value Theory. Data were collected from 2346 Chinese high school students (Mage = 15.60, S = 0.82; 44.16% boys) over a period of 3 months. The results reveal that after controlling for T1 student burnout, T1 friend burnout negatively predicts T1-T2 changes in academic self-efficacy and value (intrinsic value, attachment value, and utility value), which in turn negatively predict T2 student burnout. Thus, changes in academic self-efficacy and value completely mediate the crossover of burnout among adolescent students. These findings highlight the importance of taking into account the decline of academic motivation in understanding the crossover of burnout.

Cysteine Modification of Glutathione-Stabilized Au Nanoclusters to Red-Shift and Enhance the Electrochemiluminescence for Sensitive Bioanalysis.

Screening new electrochemiluminescence (ECL) emitters for the design of sensitive detection strategies with even long emission wavelength is intensively anticipated in ECL evolution. Herein, a promising modification strategy for improving the ECL performance of Au nanoclusters (AuNCs) as a water-soluble luminophore was proposed. Upon the introduction of l-cysteine (l-Cys) onto the surface of glutathione (GSH)-stabilized AuNCs (GSH-AuNCs), the dual-thiol bond between l-Cys and GSH was formed to limit the intramolecular motion and nonradiative relaxation of the excited state from the capping agents, which resulted in the enhancement of monochromatic ECL emission of GSH-AuNCs with a red-shifted wavelength. By utilizing triethylamine as a coreactant, the ECL of l-Cys/GSH-AuNCs was about 1.5-fold stronger than that of GSH-AuNCs, and the emission wavelength red-shifted from 660 to 780 nm at a relatively low potential, which could decrease the interference in bioassay and the photochemical damage in nondestructive detection. As a proof of application, a sandwich-type immunosensing method for CYFRA 21-1 was proposed with l-Cys/GSH-AuNCs as the signal tag, which displayed a wide linear ranging from 0.2 fg/mL to 2 ng/mL and a limit of detection down to 0.067 fg/mL at 3S/N. This work provides a wonderful strategy for promoting the performance of ECL emitters.

Wood-Derived Monolithic Catalysts with the Ability of Activating Water Molecules for Oxygen Electrocatalysis.

Oxygen reduction reaction (ORR) is the key reaction on cathode of rechargeable zinc-air batteries (ZABs). However, the lack of protons in alkaline conditions limits the rate of ORR. Herein, an activating water strategy is proposed to promote oxygen electrocatalytic activity by enhancing the proton production from water dissociation. FeP nanoparticles (NPs) are coupled on N-doped wood-derived catalytically active carbon (FeP-NWCC) to associate bifunctional active sites. In alkaline, FeP-NWCC possesses outstanding catalytic activities toward ORR (E1/2  = 0.86 V) and Oxygen evolution reaction (OER) (overpotential is 310 mV at 10 mA cm-2 ). The liquid ZABs assembled by FeP-NWCC deliver superior peak power density (144 mW cm-2 ) and cycle stability (over 450 h). The quasi-solid-state ZABs based on FeP-NWCC also display excellent performances. Theoretical calculation illustrates that the superb bifunctional performance of FeP-NWCC results from the elevated dissociation efficiency of water via FeP NPs to assist the oxygen catalytic process. The strategy of activating water provides a new perspective for the design of ORR/OER bifunctional catalysts. This work is a model for the application of forest biomass.

Coupling Fe3 C Nanoparticles and N-Doping on Wood-Derived Carbon to Construct Reversible Cathode for Zn-Air Batteries.

Electrochemical reduction of oxygen plays a critical role in emerging electrochemical energy technologies. Multiple electron transfer processes, involving adsorption and activation of O2 and generation of protons from water molecules, cause the sluggish kinetics of the oxygen reduction reaction (ORR). Herein, a double-active-site catalyst of Fe3 C nanoparticles coupled to paulownia wood-derived N-doped carbon (Fe3 C@NPW) is fabricated via an active-site-uniting strategy. One site on Fe3 C nanoparticles contributes to activating water molecules, while another site on N-doped carbon is responsible for activating oxygen molecules. Benefiting from the synergistic effect of double active sites, Fe3 C@NPW delivers a remarkable catalytic activity for ORR with a half-wave potential of 0.87 V (vs. RHE) in alkaline electrolyte, outperforming commercial Pt/C catalyst. Moreover, zinc-air batteries (ZABs) assembled with Fe3 C@NPW as a catalyst on cathode achieve a large specific capacity of 804.4 mA h gZn-1 and a long-term stability of 780 cycles. The model solid-state ZABs also display satisfactory performances with an open-circuit voltage of 1.39 V and a high peak power density of 78 mW cm-2 . These outstanding performances reach the level of first-rank among the non-noble metal electrode materials. This work offers a promising approach to creating double-active-site catalysts by the active-site-uniting strategy for energy conversion fields.

Formation of Bulk Nanobubbles Induced by Accelerated Electrons Irradiation: Dependences on Dose Rates and Doses of Irradiation.

Radiation on aqueous solutions can induce water radiolysis with products of radicals, H2, H2O2, and so on, and their consequent biological effects have long been interested in radiation chemistry. Unlike the decomposition of water by electric current that produces a significant number of bubbles, the gas products from the radiolysis of water are normally invisible by bare eyes, little is known on whether nanosized bubbles can be produced and what their dynamics are upon irradiation. Here, we first presented the formation of nanoscale bulk bubbles by irradiating pure water with accelerated electrons and their concentration and size distribution changes with the dose and rate of irradiation. The nanoparticle tracking analysis showed that irradiation can actually produce a certain amount of bulk nanobubbles in pure water. They exhibited a dependence on the irradiation dose rates and irradiation doses. The results indicated that the concentration of formed bulk nanobubbles increased as the irradiation dose rates increased, but it will increase and then decrease with the increased irradiation doses. The formed bulk nanobubbles could maintain stability for several hours. Our findings will provide a new angle of view for the radiation chemistry of water, and the formed nanobubbles may help elucidate the biological effects of irradiated solutions.

Influence of the Dissolved Gas on the Interfacial Properties of Decane Surface Nanodroplets.

Surface nanodroplets have received extensive attention recently due to their potential in the fabrication of functional materials with nanostructures and chemical reactions at micro- and nanoscales. Although the effect of dissolved gas in water has been realized in some important processes such as spontaneous emulsification of oil droplets in water, its roles in the wetting behavior of surface nanodroplets at the hydrophobic interface have been largely neglected. Here, we focused on the influence of dissolved gas on the interfacial properties of surface nanodroplets and characterized their morphological evolution when exposed to different air-saturated water samples. Results indicated that the morphology of surface nanodroplets barely changed in air-oversaturated cold water. However, their contact angle first decreases gradually in deionized water, increases immediately after replacement with degassed water, and eventually decreases gradually with time. Furthermore, the surface tension of nanodroplets would change similarly after the injection of degassed water. We considered these changes to be caused by the removal or reduction of the enriched gas at the substrate interface, in which the surface hydrophobicity was changed. Our findings could shed some light on the wetting behavior of nanodroplets at the hydrophobic surface in different air-saturated water samples and inspire the microscale manipulation and reaction of surface nanodroplets.

Controllable generation of interfacial gas structures on the graphite surface by substrate hydrophobicity and gas oversaturation in water.

Spherical nanobubbles and flat micropancakes are two typical states of gas aggregation on solid-liquid surfaces. Micropancakes, which are quasi-two-dimensional gaseous structures, are often produced accompanied by surface nanobubbles. Compared with surface nanobubbles, the intrinsic properties of micropancakes are barely understood due to the challenge of the highly efficient preparation and characterization of such structures. The hydrophobicity of the substrate and gas saturation of solvents are two crucial factors for the nucleation and stability of interfacial gas domains. Herein, we investigated the synergistic effect of the surface hydrophobicity and gas saturation on the generation of interfacial gas structures. Different surface hydrophobicities were achieved by the aging process of highly oriented pyrolytic graphite (HOPG). The results indicated that higher surface hydrophobicity and gas oversaturation could create surface nanobubbles and micropancakes with higher efficiency. Strong surface hydrophobicity could promote nanobubble nucleation and higher gas saturation would induce bigger nanobubbles. Degassed experiments could remove most of these structures and prove that they are actually gaseous domains. Finally, we draw a region diagram to describe the formation conditions of nanobubbles, micropancakes based on observations. These results would be very helpful for further understanding the formation of interfacial gas structures on the hydrophobic surface under different gas saturation.

Reply to the 'Comment on "Can bulk nanobubbles be stabilized by electrostatic interaction?"' by S. Koshoridze and Y. Levin, Phys. Chem. Chem. Phys., 2022, 24, DOI: 10.1039/D1CP04406K.

We investigated the effect of the adsorbed ions on the stability of nanobubbles suspended in the liquid in a recent article published in Physical Chemistry Chemical Physics. We calculated the electrostatic pressure using the classical electrical double layer (EDL) theory and pointed out that the electrostatic pressure is overestimated in previous theories due to the overlook of the stress in the diffusive double layer. Recently, S. I. Koshoridze and Yu. K. Levin questioned our calculations and results based on their intuition that diffusive ions in the EDL will drift and, therefore, not contribute to hydrostatic pressure. In this reply, we explain why mobile ions can also produce hydrostatic pressure from a hydrodynamic perspective.

SPI1-related protein inhibits cervical cancer cell progression and prevents macrophage cell migration.

AIM: The functions and molecular mechanisms of SPI1-related protein (SPIB) were examined in cervical cancer (CC) cells. METHODS: Genes related to miscarriage and prognosis in CC were identified by Kaplan-Meier and differential expression analysis, respectively. Cell proliferation, apoptosis, migration, and invasion were examined by cell counting kit-8, flow cytometry, transwell migration, and transwell invasion assays, respectively. The potential functions and molecular mechanisms of SPIB in CC were speculated by gene set enrichment analysis (GSEA) analysis. The mRNA and protein levels of genes were examined by RT-qPCR and western blot assays, respectively. The effect of SPIB on macrophage cells was tested by macrophage recruitment assay and bioinformatics analysis. RESULTS: A total of 753 dysregulated genes were identified in 88 TCGA CC samples with a history of one or more miscarriages versus 208 CC samples with no miscarriage history. Also, 91 genes related to CC prognosis were identified. SPIB, a gene related to both miscarriage and CC prognosis, inhibited Hela cell proliferation, migration, and invasion, and facilitated Hela cell apoptosis. GSEA analysis disclosed that SPIB might play vital roles in immunity, chemokine signaling pathway, and macrophage chemotaxis/activation in CC. Moreover, SPIB inhibited C-X-C motif chemokine ligand 8 (CXCL8), C-C motif chemokine ligand 17 (CCL17), and C-C motif chemokine ligand 25 (CCL25) expression in Hela cells, and SPIB overexpression in Hela cells hampered THP-1 cell migration. Higher SPIB expression was associated with less M2 macrophage infiltration in CC. CONCLUSIONS: SPIB inhibited CC-cell progression and hindered macrophage cell migration in CC.

Effects of a fixed nurse team in the orthopaedic surgery operating room on work efficiency and patient outcomes: a propensity score-matched historically controlled study.

BACKGROUND: The work value of operating room (OR) nurses is directly reflected in nursing quality. However, evaluating the work value of these nurses has not been sufficiently investigated. This study evaluated the effects of a fixed nurse team (FNT) in an orthopaedic surgery OR on work efficiency and patient outcomes. METHODS: A propensity score-matched historically controlled study conducted from 1 July 2015 to 30 June 2018 was used to investigate the difference in nursing quality between an FNT period and a non-FNT period in the orthopaedic surgery OR at a tertiary care hospital in China. The primary outcome was surgical site infections (SSIs) during in-hospital visits, and as a secondary outcome, other nursing-sensitive quality indicators were assessed with historically controlled data. A multifactor logistic regression model was constructed to examine the primary outcome differences between the FNT and non-FNT periods before and after propensity score matching. RESULTS: In total, 5365 patients and 33 nurses were included in the final analysis. The overall SSI rate was 2.1% (110/5365; the non-FNT period 2.6% [64/2474], the FNT period 1.6% [46/2891]). A lower incidence of SSIs in patients (odds ratio 0.57, 95% CI 0.36 to 0.88, P=0.013), a lower turnover time of the surgical procedure (odds ratio 0.653, 95% CI 0.505 to 0.844, P<0.001), and improvement in surgeon satisfaction (odds ratio 1.543, 95% CI 1.039 to 2.292, P=0.031), were associated with the FNT period compared with the non-FNT period. However, we did not find significant differences between the FNT period and the non-FNT period in terms of the other indicators. CONCLUSIONS: The presence of an FNT in an OR reduces the incidence of SSIs in surgical patients and the turnover time of surgical procedures and improves surgeon satisfaction. Further implementation of an advanced-practice nurse model with nurse specialists is encouraged.

Microenvironment Engineering for the Electrocatalytic CO2 Reduction Reaction.

Rather than just focusing on the catalyst itself in the electrocatalytic CO2 reduction reaction (eCO2 RR), as previously reviewed elsewhere, we herein extend the discussion to the special topic of the microenvironment around the electrocatalytic center and present a comprehensive overview of recent research progress. We categorize the microenvironment based on the components relevant to electrocatalytic active sites, i.e., the catalyst surface, substrate, co-reactants, electrolyte, membrane, and reactor. Supported by most of the reported articles, the relevant factors affecting the catalytic performance of eCO2 RR are then discussed in detail, and existing challenges and potential solutions are mentioned. Perspectives for the future research on eCO2 RR, including the integration of different microenvironment factors, the extension to industrial application by coupling with carbon capture and conversion, and separation of products, are also discussed.