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The in situ EXAFS experiments indicated that the Co–Ru moiety suppresses the formation of metallic Co under acidic conditions and dominates the catalytic activity of Rux@CoP electrocatalysts.

The result of probing the dynamic structure of co-sputtered CuO and ZnO electrocatalyst suggests the reversing Ostwald ripening of Cu structure is triggered during CO2RR and has a key impact on its methane selectivity.

Although the bulk properties of catalytic materials can be easily regulated by doping, the surface of them where electrocatalysis occurs often deviates from the bulk properties and is hardly controlled....

Real bifunctional electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction have to be the ones that exhibit a steady configuration during/after reaction without irreversible structural transformation or surface reconstruction. Otherwise, they can be termed as "precatalysts" rather than real catalysts. Herein, through a strongly atomic metal-support interaction, single-atom dispersed catalysts decorating atomically dispersed Ru onto a nickel-vanadium layered double hydroxide (LDH) scaffold can exhibit excellent HER and OER activities. Both

To reach a carbon-neutral future, electrochemical CO2 reduction reaction (eCO2RR) has proven to be a strong candidate for the next-generation energy system. Among potential materials, single-atom catalysts (SACs) serve as a model to study the mechanism behind the reduction of CO2 to CO, given their well-defined active metal centers and structural simplicity. Moreover, using metal-organic frameworks (MOFs) as supports to anchor and stabilize central metal atoms, the common concern, metal aggregation, for SACs can be addressed well. Furthermore, with their turnability and designability, MOF-derived SACs can also extend the scope of research on SACs for the eCO2RR. Herein, we synthesize sulfurized MOF-derived Mn SACs to study effects of the S dopant on the eCO2RR. Using complementary characterization techniques, the metal moiety of the sulfurized MOF-derived Mn SACs (MnSA/SNC) is identified as MnN3S1. Compared with its non-sulfur-modified counterpart (MnSA/NC), the MnSA/SNC provides uniformly superior activity to produce CO. Specifically, a nearly 30% enhancement of Faradaic efficiency (F.E.) in CO production is observed, and the highest F.E. of approximately 70% is identified at -0.45 V. Through operando spectroscopic characterization, the probing results reveal that the overall enhancement of CO production on the MnSA/SNC is possibly caused by the S atom in the local MnN3S1 moiety, as the sulfur atom may induce the formation of S-O bonding to stabilize the critical intermediate, *COOH, for CO2-to-CO. Our results provide novel design insights into the field of SACs for the eCO2RR.

Tin perovskite solar cells (PSCs) have been attracting attention in photovoltaic application, while the performance of Sn PSCs, especially for hole-transporting materials (HTMs)-free configuration,...

Anodic urea oxidation reaction (UOR) is an intriguing half reaction that can replace oxygen evolution reaction (OER) and work together with hydrogen evolution reaction (HER) toward simultaneous hydrogen fuel generation and urea-rich wastewater purification; however, it remains a challenge to achieve overall urea electrolysis with high efficiency. Herein, we report a multifunctional electrocatalyst termed as Rh/NiV-LDH, through integration of nickel-vanadium layered double hydroxide (LDH) with rhodium single-atom catalyst (SAC), to achieve this goal. The electrocatalyst delivers high HER mass activity of 0.262 A mg

A coupling catalyst of highly dispersed N, P co-doped carbon frames (NPCFs) anchored with Fe single atoms (SAs) and Fe

Strong catalyst–support interaction plays a key role in heterogeneous catalysis, as has been well-documented in high-temperature gas-phase chemistry, such as the water gas shift reaction. Insight i...

Understanding the dynamic structural reconstruction/transformation of catalysts during electrochemical CO2 reduction reaction (CO2RR) is highly desired for developing more efficient and selective catalysts, yet still lacks in-depth realization. Herein, we study a model system of copper nanowires with various degrees of silver modifications as electrocatalysts for CO2RR. Among them, the Cu68Ag32 nanowire catalyst achieves the highest activity and selectivity toward methane with an extremely high faradaic efficiency of ∼60%, about 3 times higher than that of primitive Cu nanowires, and even surpasses the most efficient catalysts for producing methane. By using in situ grazing-angle X-ray scattering/diffraction, X-ray absorption spectroscopy, and Raman techniques, we found that the Cu68Ag32 nanowires underwent an irreversible structural reconstruction and well-stabilized chemical state of Cu on the catalyst surface under the working CO2RR conditions, which greatly facilitates the CO2 to methane conversion. Further analysis reveals that the restructuring phenomenon can be ascribed to a reoxidation/reduction-driven atomic interdiffusion between Cu and Ag. This work reveals the first empirical demonstration by deploying comprehensive in situ techniques to track the dynamic structural reconstruction/transformation in a model bimetallic system, which not only establishes a good understanding of the correlation between catalyst surface structure and catalytic selectivity but also provides deep insights into designing more developed electrocatalysts for CO2RR and beyond.

The oxygen evolution reaction (OER) is crucial in electrochemical water splitting and metal-air battery, and demands a low cost, efficient and durable electrocatalyst. An ideal OER catalyst should ...

In the face of climate change and rising energy consumption, electrocatalysis for the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and CO2 reduction reaction (CO2RR) have become promising catalytic processes to address these critical issues. By integrating OER and HER/CO2RR with renewable energy, it may potentially provide a promising way for a sustainable human society. Nonetheless, lack of understanding of catalysts under working conditions and reaction mechanisms restrict the development of efficient catalysts. In recent years, in situ techniques that can be used to investigate the structural transformation of catalysts during the reaction have attracted considerable research interest. Herein, recent developments in heterogeneous catalysts for OER, HER, and CO2RR explored by using in situ X-ray diffraction and X-ray absorption spectroscopy techniques have been comprehensively summarized. Finally, challenges and future perspectives in this field are also provided to pave the way for future developments.

Unraveling the reaction mechanism behind the CO2 reduction reaction (CO2RR) is a crucial step for advancing the development of efficient and selective electrocatalysts to yield valuable chemicals. To understand the mechanism of zinc electrocatalysts toward the CO2RR, a series of thermally oxidized zinc foils is prepared to achieve a direct correlation between the chemical state of the electrocatalyst and product selectivity. The evidence provided by in situ Raman spectroscopy, X-ray absorption spectroscopy (XAS) and X-ray diffraction significantly demonstrates that the Zn(II) and Zn(0) species on the surface are responsible for the production of carbon monoxide (CO) and formate, respectively. Specifically, the destruction of a dense oxide layer on the surface of zinc foil through a thermal oxidation process results in a 4-fold improvement of faradaic efficiency (FE) of formate toward the CO2RR. The results from in situ measurements reveal that the chemical state of zinc electrocatalysts could dominate the product profile for the CO2RR, which provides a promising approach for tuning the product selectivity of zinc electrocatalysts.

Utilizing renewable electricity energy to convert CO

Accounting for biotic interactions is important for predicting species and ecosystem variation under changing climate but difficult to achieve in practice. The proportion of geographical overlap between species, called species geographical sensitivity (SGS), could be used to gauge the potential for species interactions. Species with increasingly high SGS could have the potential to experience more interactions with other species and vice versa, which might have important implications in ecological assessment, particularly at a community level, in the face of climate change. We compiled fish occurrences in the North Sea from 1983 to 2020 and calculated annual mean SGS (mSGS) to systematically evaluate their temporal changes and to estimate influences of species traits on the relative temporal changes in mSGS. The results showed that 36.3% of species significantly changed their mSGS over time, with high correlations between changes in species range size and overlap with other species. The species’ averaged mSGS before warming was highly correlated with the relative change in mSGS. Depth range, body length, and age at maturity together explained most variation in mSGS among these species. Contemporary climate change is expected to reorganize species distributions and interactions and substantially alter marine ecosystem functioning. Our assessment opens a new avenue for evaluating climate change impacts on species geographical interactions, and such geographical changes may be contingent on species traits.

To reach a carbon-neutral future, electrochemical CO

Oxide-derived copper catalysts have been shown to enhance CO2 reduction reaction (CO2RR) activity with high selectivity toward hydrocarbon products. However, the chemical state of oxide-derived copper during the CO2RR has remained elusive and is lacking in situ observations. Herein, a two-step process was developed to synthesize Ag nanowires coated with various thicknesses of a CuOx layer for the CO2RR. By employing in situ X-ray absorption spectroscopy, a strong correlation between the chemical state under reaction conditions and the CO2RR product profile can be revealed to validate another competing reaction (i.e., the spontaneous oxidation of Cu(0) in aqueous electrolyte) that significantly governs the chemical state of active centers of Cu. In situ Raman spectroscopy reveals the existence of reoxidation behavior under cathodic potential, and the quantification analysis of reoxidized behavior is revealed to indicate that the reoxidation rate is independent of surface morphology and strongly proportional to the electrochemically surface area. The steady oxidation state of Cu in an in situ condition is the paramount key and dominates the products’ profile of the CO2RR rather than other factors (e.g., crystal facets, atomic arrangements, morphology, elements) that have been investigated in numerous reports., In situ X-ray absorption spectroscopy elucidates the spontaneous reoxidation of Cu that affects the steady chemical states that were revealed to dominate the product profile of electrochemical CO2 reduction.

Phosphide-based electrocatalysts exhibit high activities in alkaline solution toward overall water electrolysis. However, their real phases during catalysis have not been comprehensively identified...

The discovery of different binding receptors to allow rapid and high-sensitivity detection via a noninvasive urine test has become the goal for urothelial carcinoma (UC) diagnosis and surveillance. In this study, we developed a new screening membrane receptor platform for bladder cancer cells by integrating surface-enhanced Raman spectroscopy (SERS) with 4-aminothiophenol (4-ATP)-modified AuAg nanohollows upon NIR laser excitation. AuAg nanohollows have an absorption band at ∼630 nm, and slightly off-resonance 785 nm laser excitation is used for minimal photothermal effect. Using the same carbodiimide cross-linker chemistry to conjugate anti-EGFR, transferrin (TF), 4-carboxyphenylboronic acid (CPBA), folic acid (FA), and hyaluronic acid (HA) molecules, by screening the 4-ATP SERS signals intensity, we demonstrated that the targeting efficiency with the cost-effective CPBA molecule is comparable with the conjugation of anti-EGFR antibody to aggressive T24 cancer cells (high-grade), while weak intensity 4-ATP SERS responses to targets were obtained by grade-I RT4 bladder cancer cells, NIH/3T3 fibroblast cells, and SV-HUC1 bladder normal cells. This SERS nanoprobe platform makes primary bladder carcinoma screening from in vitro to ex vivo more straightforward. Our demonstration offers exciting potential for SERS screening of specific receptors on cancer cells of different grades and facilitates new opportunities ranging from surface engineering of SERS material tags to SERS imaging-guided and targeted phototherapy of cancer cells by controlling the laser powers.

We have revealed that cubelike and hexarhombic docadehedron-like Cu single crystals showed an enhancement of C2 products (ethylene and ethanol) while octahedron-like Cu nanoscale single crystals pr...

The question of whether the metal chalcogenides (phosphides) that have been acknowledged to be efficient materials for bifunctional electrocatalysts really perform as the active species or just “pre-catalysts” has been debated. Herein, a series of operando measurements, including in situ X-ray absorption spectroscopy, liquid-phase transmission electron microscopy, and in situ Raman spectroscopy, were conducted to unravel in real time the structural and chemical stability of P-substituted CoSe2 electrocatalysts under both hydrogen and oxygen evolution reactions (HER and OER, respectively) in an alkaline electrolyte. It can be conclusively revealed that, in an alkaline electrolyte, the P-substituted CoSe2 electrocatalyst was acting as the “pre-catalyst” rather than the real reactive species. The introduction of phosphorus is speculated to generate more vacancies or defects around Co cations in the initial CoSe2 and considerably facilitates the structural transformation into the “real reactive species”, such...

Heterogeneous catalysis based on air-stable lanthanide complexes is relatively rare, especially for electrochemical water oxidation and reduction. Therefore, it is highly desired to investigate the synergy caused by cocatalysts on the lanthanide complex family for heterogeneous catalysis because of their structural diversity, air/moisture insensitivity, and easy preparation under an air atmosphere. Two mononuclear and three dinuclear dysprosium complexes containing a series of Schiff-base ligands have been demonstrated as robust electrocatalysts for triggering heterogeneous water oxidation in alkaline solution, in which the complex [Dy2(hmb)2(OAc)4]·MeCN(3) was revealed to have the best activity toward heterogeneous water oxidation among all five complexes in the present study. The molecular activation of dysprosium complexes has also been investigated with a series of N-containing heterocyclic additives [i.e., 4-(dimethylamino)pyridine (DMAP), bis(triphenylphosphine)iminium chloride ([PPN]Cl), indole, and quinoline]. In particular, the corresponding overpotential was effectively enhanced by 211 mV (at a current density of 10 mA cm-2) with the assistance of DMAP. On the basis of electrochemical and ex situ/in situ spectroscopic investigations, the best catalyst, DMAP-complex 3 on a carbon paper electrode, was confirmed with well-maintained molecular identity during heterogeneous water oxidation free of forming any dysprosium oxide and/or undesired products.

Real bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) should be the ones that exhibit an immortal behavior during catalysis without structural transformation or surface reconstruction. Otherwise, they could be only termed as “pre-catalysts” rather than the real catalysts. Herein, single-atom dispersed catalysts (SACs) embedding atomically dispersed Ru onto nickel-vanadium layered double hydroxide matrix (termed as Ru/Ni3V-LDH) not only exhibit excellent HER activity (~ 54.3 fold mass activity vs. the commercial Pt/C) and OER activity, but also possess decent full-cell performance for overall water splitting (1.5 V@10 mA cm-2). Most importantly, in-situ XAS and Raman spectroscopic studies clarified that, unlike numerous bifunctional catalysts that have suffered from the structural reconstruction/transformation for adapting the HER/OER cycles, Ru/Ni3V-LDH is characteristic of immortally dual reactive sites (i.e., Ru and Ni sites) for individual catalysis of electrochemical water splitting and could be termed as the real bifunctional electrocatalyst.

Unraveling the reaction mechanism behind the CO

Understanding the dynamic structural reconstruction/transformation of catalysts during electrochemical CO

In this article, a series of single-phase NixMn1-x(OH)2 hydroxides with x=1, 3/4, 2/4, 1/4 and 0 have been prepared by coprecipitation reaction. The effect of chemical composition of the NixMn1-x(OH)2 hydroxides on the capacitive characteristics has been systematically investigated. Density functional theory (DFT) calculations indicate that the incorporation of Mn ions into Ni(OH)2 hydroxide can reduce the deprotonation energy and energy gap leading to better electron transport. However, the morphological structure of the hydroxides also becomes larger and coarser with decreasing the x value from 1 to 0, which is unfavorable for the electrochemical performance. Therefore, there is a trade-off between deprotonation energy, band gap, morphology and surface area to achieve high-performance capacitive materials. The results demonstrate Ni3/4Mn1/4(OH)2 hydroxide with the optimal chemical composition shows the best electrochemical performance with a capacitance of 758.7 F g−1 at 1 A g−1 and excellent rate performance of 517.6 F g−1 at 10 A g−1. The asymmetric supercapacitors incorporated with Ni3/4Mn1/4(OH)2 and active carbon (AC) also exhibit a high energy density of 40.7 Wh kg−1 at power density of 800 W kg−1 and remarkable cycling life along with 94.4% retention after 3000 cycles.

Roughing the metallic surface via oxidation-reduction cycles (ORC) to integrate the surface plasmon resonance and surface-enhanced Raman scattering (SERS) is predominant in developing sensor systems because of the facile preparation and uniform distribution of nanostructures. Herein, we proposed a distinctive ORC process: the forward potential passed through the oxidation of Au and reached the oxygen evolution reaction, and once the potential briefly remained at the vertex, the various reverse rates were employed to control the reduction state. The created hybrid Au-AuO x possessed electromagnetic and chemical enhancements concurrently, wherein the rough surface provided the strong local electromagnetic fields and significant interaction between AuO x and molecule to improve the charge transfer. The synergistic effects significantly amplified the intensity of Raman signal with an enhancement factor of 5.5 × 106 under the optimal conditions. Furthermore, the prepared SERS substrate can simultaneously identify and quantify the mixed edible pigments, Brilliant Blue FCF and Indigo Carmine, individually. This result suggested that the development of SERS sensor based on the proposed SERS-activated methodology is feasible and reliable.

Water scarcity is one of the most serious global challenges of our time. One of the currently resolutions to this shortage is desalination. So far, most research on desalination has focused on preparing photothermal materials which possess the property of light-to-heat conversion. However, changing the intrinsic properties of water to improve the efficiency of solar evaporation has rarely been discussed. A new concept to increase the efficiency of desalination via destroying hydrogen bonds based on gold nanoparticles-adsorbed ceramic rods (AuNPs@CRs) is proposed here for the first time. Weakening the strength of interactions within water molecules by illumination with resonant light produces easily evaporable plasmon-activated water (PAW). This proposed system exhibits high efficiencies of steam generation in different experimental environments. Meanwhile, it was 140.0% and 107.5% more efficient than untreated water in an oven and an indoor environment, respectively. The source of resonant light from sunlight on a sunny or cloudy day can also achieve this performance. In addition, the results of water pump suction and direct contact membrane distillation (DCMD) further demonstrated that the illuminated AuNPs@CR system exhibits high potential for desalination.

The strength of hydrogen bonds (HBs) decides water’s properties and activities. It is recognized that the properties of confined liquid water, or liquid water in contact with hydrophobic surfaces, significantly differ from those of bulk liquid water. However, these unique properties of water are only found within the interfacial phase and a confined environment; thus, their applications are limited. Nowadays, environmentally friendly science, health and energy are main concerns in the world. In this review, an innovative and facile method for preparing mass-produced plasmon-activated water (PAW) with reduced HBs by letting bulk water flow through gold-supported nanoparticles (AuNPs) under resonant illumination at constant temperature is reported. The resulting stable PAW exhibits distinct properties and activities, which significantly differ from those of untreated bulk water. In addition, this PAW has the obvious advantages in environmentally friendly science, green energy, water saving and medicine.

Conventionally, electrochemical polymerization of polypyrrole (PPy) was generally performed in deionized (DI) water-based electrolyte. In this work, an innovative and facile strategy to substantially enhance the electroactive surface areas of electrochemically polymerized PPy is proposed by using plasmon-activated water (PAW)-based electrolyte. Compared to the DI water-based system, the prepared PPy with higher electron transfer rate and more-reversible redox performance was observed by using PAW-based system. In addition, a greater electroactive surface area of three-dimensional PPy was obtained with PAW-based electrolyte. These distinct properties of PPy electrodes prepared with PAW were responsible for their better performances in supercapacitors (with ca. 25.2% increased capacitance) and sensors (with ca. 50.0% increased sensitivity), compared to those prepared with DI water. These encouraging findings show the potential of PPy prepared with newly developed PAW for application to PPy-related devices to further enhance various performances.