MXene-mediated reconfiguration induces robust nickel-iron catalysts for industrial-grade water oxidation.

Nickel-iron oxy/hydroxides (NiFeOxHy) emerge as an attractive type of electrocatalysts for alkaline water oxidation reaction (WOR), but which encounter a huge challenge in stability, especially at industrial-grade large current density due to uncontrollable Fe leakage. Here, we tailor the Fe coordination by a MXene-mediated reconfiguration strategy for the resultant NiFeOxHy catalyst to alleviate Fe leakage and thus reinforce the WOR stability. The introduction of ultrafine MXene with surface dangling bonds in the electrochemical reconfiguration over Ni-Fe Prussian blue analogue induces the covalent hybridization of NiFeOxHy/MXene, which not only accelerates WOR kinetics but also improves Fe oxidation resistance against segregation. As a result, the NiFeOxHy coupled with MXene exhibits an extraordinary durability at ampere-level current density over 1,000 h for alkaline WOR with an ultralow overpotential of only 307 mV. This work provides a broad avenue and mechanistic insights for the development of nickel-iron catalysts toward industrial applications.

Enhanced Charge Separation in Nanoporous BiVO4 by External Electron Transport Layer Boosts Solar Water Splitting.

The optimization of charge transport with electron-hole separation directed toward specific redox reactions is a crucial mission for artificial photosynthesis. Bismuth vanadate (BiVO4 , BVO) is a popular photoanode material for solar water splitting, but it faces tricky challenges in poor charge separation due to its modest charge transport properties. Here, a concept of the external electron transport layer (ETL) is first proposed and demonstrated its effectiveness in suppressing the charge recombination both in bulk and at surface. Specifically, a conformal carbon capsulation applied on BVO enables a remarkable increase in the charge separation efficiency, thanks to its critical roles in passivating surface charge-trapping sites and building external conductance channels. Through decorated with an oxygen evolution catalyst to accelerate surface charge transfer, the carbon-encased BVO (BVO@C) photoanode manifests durable water splitting over 120 h with a high current density of 5.9 mA cm-2 at 1.23 V versus the reversible hydrogen electrode (RHE) under 1 sun irradiation (100 mW cm-2 , AM 1.5 G), which is an activity-stability trade-off record for single BVO light absorber. This work opens up a new avenue to steer charge separation via external ETL for solar fuel conversion.

Orderly Nanodendritic Nickel Substitute for Raney Nickel Catalyst Improving Alkali Water Electrolyzer.

The development of nonprecious metal catalysts to meet the activity-stability balance at industrial-grade large current densities remains a challenge toward practical alkali-water electrolysis. Here, this work develops an orderly nanodendritic nickel (ND-Ni) catalyst that consists of ultrafine nanograins in chain-like conformation, which shows both excellent activity and robust stability for large current density hydrogen evolution reaction (HER) in alkaline media, superior to currently applied Raney nickel (R-Ni) catalyst in commercial alkali-water electrolyzer (AWE). The ND-Ni catalyst featured by a three-dimensional (3D) interconnecting microporous structure endows with high specific surface area and excellent conductivity and hydrophilicity, which together afford superior charge/mass transport favorable to HER kinetics at high current densities. An actual AWE with ND-Ni catalyst demonstrates durable water splitting with 1.0 A cm-2 at 1.71 V under industrial conditions and renders a record-low power consumption of 3.95 kW h Nm-3 with an energy efficiency close to 90%. The hydrogen price per gallon of gasoline equivalent (GGE) is calculated to be ≈$0.95, which is less than the target of $2.0 per GGE by 2026 from the U.S. Department of Energy. The results suggest the feasibility of ND-Ni substitute for R-Ni catalyst in commercial AWE.

Micropapillary or solid component predicts worse prognosis in pathological IA stage lung adenocarcinoma: A meta-analysis.

BACKGROUND: Micropapillary and solid patterns indicate worse survival in lung adenocarcinoma patients, even in pathological stage IB patients. However, whether the presence of micropapillary or solid components is related to worse prognosis in pathological IA stage lung adenocarcinoma remains unclear. METHODS: Several databases were searched up to December 31, 2022 for relevant studies investigating the association between micropapillary and solid components and the survival of IA stage lung adenocarcinoma patients. Primary and secondary outcomes are disease-free survival (DFS) and overall survival (OS), respectively. Hazard ratios (HRs) and 95% confident intervals (CIs) were combined, and subgroup analysis stratified by the pathological subtype and proportion of components was further performed. RESULTS: A total of 19 studies with 12,562 cases were included. Pooled results indicated that micropapillary or solid components obviously predicted worse DFS (HR = 2.40, 95% CI: 1.96-2.94, P < .001) and OS (HR = 2.30, 95% CI: 1.68-3.15, P < .001). Subgroup analysis based on pathological subtype showed that both micropapillary and solid components were significantly associated with worse DFS (micropapillary: HR = 2.70, 95% CI: 1.70-4.28, P < .001; solid: HR = 3.98, 95% CI: 2.10-7.54, P < .001) and OS (micropapillary: HR = 2.29, 95% CI: 1.17-4.48, P = .015; solid: HR = 4.18, 95% CI: 1.72-10.17, P = .002). In addition, further subgroup analysis stratified by the proportion of micropapillary and solid components (>5%/1% or predominant) showed similar results. CONCLUSION: Micropapillary and solid patterns predicted a significantly worse prognosis in pathological IA stage lung adenocarcinoma patients.

Adsorption and sensing performance of air pollutants on a ß-TeO2 monolayer: a first-principles study.

Two-dimensional (2D) ß-TeO2 is a novel semiconductor with potential applications in electronic circuits due to its air-stability and ultra-high carrier mobility. In this study, we explore the possibility of using a 2D ß-TeO2 monolayer for the detection of gaseous pollutants including SO2, NO2, H2S, CO2, CO, and NH3 gas molecules based on first-principles calculations. The adsorption properties including the adsorption energy, adsorption distance and charge transfer indicate that the interaction between 2D ß-TeO2 and the six gases is via a physisorption mechanism. Among the six gas adsorption systems, the SO2 adsorption system has the most negative adsorption energy and the largest charge transfer. In addition, the adsorption of SO2 obviously changes the electrical conductivity of the ß-TeO2 monolayer because the band gap decreases from 2.727 eV to 1.897 eV after adsorbing SO2. Our results suggest that the 2D ß-TeO2 should be an eminently promising SO2 sensing material.

Iron-Locked Hydr(oxy)oxide Catalysts via Ion-Compensatory Reconstruction Boost Large-Current-Density Water Oxidation.

Nickel-iron based hydr(oxy)oxides have been well recognized as one of the best oxygen-evolving catalysts in alkaline water electrolysis. A crucial problem, however, is that iron leakage during prolonged operation would lead to the oxygen evolution reaction (OER) deactivation over time, especially under large current densities. Here, the NiFe-based Prussian blue analogue (PBA) is designed as a structure-flexible precursor for navigating an electrochemical self-reconstruction (ECSR) with Fe cation compensation to fabricate a highly active hydr(oxy)oxide (NiFeOx Hy ) catalyst stabilized with NiFe synergic active sites. The generated NiFeOx Hy catalyst exhibits the low overpotentials of 302 and 313 mV required to afford large current densities of 500 and 1000 mA cm-2 , respectively. Moreover, its robust stability over 500 h at 500 mA cm-2 stands out among the NiFe-based OER catalysts reported previously. Various in/ex situ studies indicate that the Fe fixation by dynamic reconstruction process can reinforce the Fe-activated effect on the OER amenable to the industrial-level large current conditions against the Fe leakage. This work opens up a feasible strategy to design highly active and durable catalysts via thermodynamically self-adaptive reconstruction engineering.

Orbital Modulation with P Doping Improves Acid and Alkaline Hydrogen Evolution Reaction of MoS2.

There has been great interest in developing and designing economical, stable and highly active electrocatalysts for the hydrogen evolution reaction (HER) via water splitting in an aqueous solution at different pH values. Transition-metal dichalcogenides (TMDCs), e.g., MoS2, are identified to be promising catalysts for the HER due to the limited active sites at their edges, while the large basal plane of MoS2 is inert and shows poor performance in electrocatalytic hydrogen production. We theoretically propose orbital modulation to improve the HER performance of the basal plane of MoS2 through non-metal P doping. The substitutional doping of P provides empty 3pz orbitals, perpendicular to the basal plane, can enhance the hydrogen adsorption for acid HER and can promote water dissociation for alkaline HER, which creates significant active sites and enhances the electronic conductivity as well. In addition, 3P-doped MoS2 exhibits excellent HER catalytic activity with ideal free energy at acid media and low reaction-barrier energy in alkaline media. Thus, the doping of P could significantly boost the HER activity of MoS2 in such conditions. Our study suggests an effective strategy to tune HER catalytic activity of MoS2 through orbital engineering, which should also be feasible for other TMDC-based electrocatalysts.

3d Transition metal doping induced charge rearrangement and transfer to enhance overall water-splitting on Ni3S2 (101) facet: a first-principles calculation study.

Cost-efficient bifunctional electrocatalysts with good stability and high activity are in great demand to replace noble-metal-based catalysts for overall water-splitting. Ni3S2 has been considered a suitable electrocatalyst for either the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) owing to its good conductivity and stability, but high performance remains a challenge. Based on density functional theory calculations, we propose a practical 3d-transition-metal (TM = Mn, Fe and Co) doping to enhance the catalytic performance for both HER and OER on the Ni3S2 (101) facet. The enhancement originates from TM-doping-induced charge rearrangement and charge transfer, which increases the surface activity and promotes catalytic behavior. In particular, Mn-doped Ni3S2 shows good bifunctional catalytic activity because it possesses more active sites, reduced hydrogen adsorption free energy (ΔG H*) for HER and low overpotential for OER. Importantly, this work not only provides a feasible means to design efficient bifunctional electrocatalysts for overall water-splitting but also provides insights into the mechanism of improving catalytic behavior.

Metformin Synergizes with PD-L1 Monoclonal Antibody Enhancing Tumor Immune Response in Treating Non-Small Cell Lung Cancer and Its Molecular Mechanism Investigation.

Despite non-small cell lung cancer (NSCLC) treatment is proved to be effective using PD-L1 monoclonal antibody (PD-L1 MAb), it is commonly seen in immune-related adverse events reported. We aimed to explore metformin synergized with PD-L1 MAb in treating NSCLC and its potential molecular mechanism. In mice, the transplantable lung cancer models were established and a co-culture system of CD8+T cells and LLC cells was constructed. The anti-tumor effect was assessed by xenograft tumor growth, proliferation signal Ki67 expression, and MTT assays. Immunohistochemistry and western blot assays were also conducted to determine tumor immune response as well as mechanism investigation. The results indicated that tumor volume and cell proliferation were markedly inhibited following metformin synergized with PD-L1 MAb which was more effective than either single metformin or PD-L1 MAb. The cytokines TNF-α, IL-2, and IFN-γ secretion in CD8+ T cells was significantly increased, and the immune response was enhanced by metformin synergized with PD-L1 MAb. Further, the WB results implied that metformin synergized with PD-L1 MAb could activate the AMPK pathway and inhibit mTOR. AMPK inhibitor (Compound C) was added, and the results showed that the anti-tumor effect was reduced in metformin + PD-L1 MAb + CC than in metformin + PD-L1 MAb which indicates the metformin synergized with PD-L1 MAb efficacy was AMPK pathway dependent. In conclusion, metformin synergized with PD-L1 MAb has better efficacy against NSCLC than metformin or PD-L1 MAb alone in an AMPK-dependent way and facilitates increasing CD8+ T cell infiltration and enhancing tumor immune response.

Chameleon-Like Reconstruction on Redox Catalysts Adaptive to Alkali Water Electrolysis.

Pre-catalyst reconstruction in electrochemical processes has recently attracted intensive attention with mechanistic potentials to uncover really active species and catalytic mechanisms and advance targeted catalyst designs. Here, nickel-molybdenum oxysulfide is deliberately fabricated as pre-catalyst to present a comprehensive study on reconstruction dynamics for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkali water electrolysis. Operando Raman spectroscopy together with X-ray photoelectron spectroscopy and electron microscopy capture dynamic reconstruction including geometric, component and phase evolutions, revealing a chameleon-like reconstruction self-adaptive to OER and HER demands under oxidative and reductive conditions, respectively. The in situ generated active NiOOH and Ni species with ultrafine and porous textures exhibit superior OER and HER performance, respectively, and an electrolyzer with such two reconstructed electrodes demonstrates steady overall water splitting with an extraordinary 80% electricity-to-hydrogen (ETH) energy conversion efficiency. This work highlights dynamic reconstruction adaptability to electrochemical conditions and develops an automatic avenue toward the targeted design of advanced catalysts.

Pronounced Linewidth Narrowing of Vertical Metallic Split-Ring Resonators via Strong Coupling with Metal Surface.

We theoretically study the plasmonic coupling between magnetic plasmon resonances (MPRs) and propagating surface plasmon polaritons (SPPs) in a three-dimensional (3D) metamaterial consisting of vertical Au split-ring resonators (VSRRs) array on Au substrate. By placing the VSRRs directly onto the Au substrate to remove the dielectric substrates effect, the interaction between MPRs of VSRRs and the SPP mode on the Au substrate can generate an ultranarrow-band hybrid mode with full width at half maximum (FWHM) of 2.2 nm and significantly enhanced magnetic fields, compared to that of VSRRs on dielectric substrates. Owing to the strong coupling, an anti-crossing effect similar to Rabi splitting in atomic physics is also obtained. Our proposed 3D metamaterial on a metal substrate shows high sensitivity (S = 830 nm/RIU) and figure of merit (FOM = 377), which could pave way for the label-free biomedical sensing.

Engineering Self-Reconstruction via Flexible Components in Layered Double Hydroxides for Superior-Evolving Performance.

Most transition metal-based catalysts for electrocatalytic oxygen evolution reaction (OER) undergo surface reconstruction to generate real active sites favorable for high OER performance. Herein, how to use self-reconstruction as an efficient strategy to develop novel and robust OER catalysts by designing pre-catalysts with flexible components susceptible to OER conditions is proposed. The NiFe-based layered double hydroxides (LDHs) intercalated with resoluble molybdate (MoO4 2- ) anions in interlayers are constructed and then demonstrated to achieve complete electrochemical self-reconstruction (ECSR) into active NiFe-oxyhydroxides (NiFeOOH) beneficial to alkaline OER. Various ex situ and in situ techniques are used to capture structural evolution process including fast dissolution of MoO4 2- and deep reconstruction to NiFeOOH upon simultaneous hydroxyl invasion and electro-oxidation. The obtained NiFeOOH exhibits an excellent OER performance with an overpotential of only 268 mV at 50 mA cm-1 and robust durability over 45 h, much superior to NiFe-LDH and commercial IrO2 benchmark. This work suggests that the ECSR engineering in component-flexible precursors is a promising strategy to develop highly active OER catalysts for energy conversion.

Enhancing the photocatalytic hydrogen production activity of BiVO4 [110] facets using oxygen vacancies.

The activity of the hydrogen evolution reaction (HER) during photoelectrochemical (PEC) water-splitting is limited when using BiVO4 with an exposed [110] facet because the conduction band minimum is below the H+/H2O potential. Here, we enhance the photocatalytic hydrogen production activity through introducing an oxygen vacancy. Our first-principles calculations show that the oxygen vacancy can tune the band edge positions of the [110] facet, originating from an induced internal electric field related to geometry distortion and charge rearrangement. Furthermore, the induced electric field favors photogenerated electron-hole separation and the enhancement of atomic activity. More importantly, oxygen-vacancy-induced electronic states can increase the probability of photogenerated electron transitions, thus improving optical absorption. This study indicates that oxygen-defect engineering is an effective method for improving the photocatalytic activity when using PEC technology.

The mechanism of enhanced photocatalytic activity for water-splitting of ReS2 by strain and electric field engineering.

To enhance the photocatalytic water splitting performance of 2D ReS2, we theoretically propose a feasible strategy to engineer its band structure by applying strain or an electric field. Our calculated results show that the strains greatly tune the electronic structure of ReS2 especially band gap and band edge positions, because the strains significantly alter the crystal structure and then cause rearrangement of the surface charge. However, electric fields have little influence on band gap but obviously affect the band edge positions. This is because the electric fields have little effect on the crystal structure of ReS2 but easily produce an in-plane electric dipole moment. The shifts in band edge position mainly arise from competition between the surface charge and the in-plane electric dipole. For an applied strain, the shifts are dominated by rearrangement of surface charge; for an applied electric field, the shifts are determined by an induced electric dipole moment. Importantly, functionalized ReS2 with a bi-axial strain of -4% or an electronic field of -0.1 V Å-1 may be good candidates for water-splitting photocatalysts owing to their suitable band edge positions for water splitting, ideal band gaps, good stability, reduced electron-hole recombination and high carrier mobility. We hope our findings will stimulate experimental efforts to develop new photocatalysts based on functionalized ReS2.

The interactions between spin wave and stacked domain walls.

In this study, the interactions between spin wave (SW) and stacked domain walls in a magnetic nanostrip are investigated via micromagnetic simulation. It is found that under the excitation of SW, the metastable TWVW structure consisting of a transverse wall (TW) and a vortex wall (VW) may transform into a 360° wall or may completely annihilate depending on the frequency and amplitude of the SW. In contrast, stacked TWs (STWs) structure shows good robustness. Similar to a single TW, the STWs can be moved by SW and the inside TWs exhibit coherent motions. Notably, the frequency dependence of STWs' velocity demonstrates obvious emergence, shift and disappearance of the resonant peaks. Such changes are found to be in accordance with SW reflection, which thus agrees with the mechanism of linear momentum transfer torque (LMTT). In concern with the SW transmission through STWs, we show that by varying TWs number and SW frequency, a wide range of transmission efficiency η can be obtained. At certain frequencies, η may increase with TWs number and may go beyond 100%, which indicates a lowered attenuation by STWs. On the other hand, the phase shift of the transmitted SW always increases linearly with the TWs number and can be resonantly enhanced at frequencies same as that of TWs normal modes. Mapping of SW reveals that the phase shift is a result of fast propagation of SW through TWs. The fast propagation and the low attenuation of SW through STWs suggests that STWs may serve as an excellent SW channel. Meanwhile, the induced STWs motion and the controlled SW transmission and phase shift by STWs also promises great uses of STWs in future magnonic devices and domain wall devices.

The origin of spin wave pulse-induced domain wall inertia.

The fundamental problem of domain wall (DW) inertia-the property that gives to inertial behaviors remains unclear in the physics of magnetic solitons. To understand its nature as well as to achieve accurate DW positioning and efficient manipulation of domain wall motion (DWM), spin wave (SW) pulse-induced DW transient effect is studied both numerically and theoretically in a magnetic nanostrip. It is shown for the first time that there occurs inevitable deceleration/automotion after SW pulse, which indicates nonzero DW inertia. The induced DWM is revealed to relate to two factors: energy storing within DW and out-of-plane tilting of DW. To explain the DWM dynamics, a one-dimensional collective model is developed to account for the excitation of spin wave pulse. The model successfully bridges DW energy, DW tilting and DW displacement and provides descriptions in accordance with numerical findings. It is made clear that the DW automotion hence DW inertia originate from the process of DW relaxation toward equilibrium. The DW inertia is expressed in terms of effective mass and turns out to be a time-dependent function with damping constant α as the governing parameter, which opposes the nature of intrinsic mass. For case containing multiple DWs, the total effective mass is shown to concern the reached velocity and stored energy of DWs instead of the number of DWs, which is against common intuition.

Functionalization of two-dimensional 1T'-ReS2 with surface ligands for use as a photocatalyst in the hydrogen evolution reaction: a first-principles calculation study.

Density functional theory calculations were performed to tune the band edge positions of two-dimensional 1T'-ReS2 by functionalization with surface ligands. A shift in the band edge was caused by the intrinsic dipole of the ligand and the induced dipole at the ligand/ReS2 interface. The upward shift in the band edge was tuned over a large range by choosing suitable polar ligands, controlling the surface coverage by the ligand, functionalizing the ligand and building heterostructures. The C6H5CN/ReS2/MoS2 and C6H5CH2CN/ReS2/MoS2 van der Waals heterostructures are ideal candidates for use as photocatalysts in the splitting of water as a result of their strong absorption in the visible region, suitable band edge positions, reduced electron-hole recombination and good stability. Our findings show the potential for creating novel photocatalysts based on van der Waals heterostructures of ReS2.

Transition metal doping activated basal-plane catalytic activity of two-dimensional 1T'-ReS2 for hydrogen evolution reaction: a first-principles calculation study.

The two-dimensional 1T' phase of ReS2 has a unique structure and its electronic properties are independent of its thickness. These features distinguish ReS2 from other two-dimensional transition metal dichalcogenides (TMDCs) used as catalysts in the hydrogen evolution reaction (HER) and suggest that it may be a suitable alternative catalyst to the expensive Pt most commonly in this reaction. Similar to traditional TMDCs, the catalytic activity of ReS2 is mainly contributed by the edge sites, whereas the basal plane, which accounts for a large percentage of the surface area, has poor catalytic activity. Activation of the basal plane of ReS2 would be an ideal strategy by which to boost its catalytic performance. We used density functional theory calculations to show that the catalytic activity of the ReS2 basal plane can be efficiently activated by doping with transition metal (TM) atoms such as Mo, Cr, Mn, Fe, Co, Pt, Au and Ag. Our results indicate that doping with a TM not only significantly reduces the hydrogen adsorption free energy (ΔGH*) of ReS2 by tuning the adsorption behavior of the H atom on the ReS2 surface, but can also expose more active sites by introducing more unsaturated electrons. Pt-doped ReS2 showed the highest catalytic activity for the HER of all the TM-doped ReS2 systems investigated, with ΔGH* = 0, a low reaction barrier and an increased density of active sites on the basal plane. More importantly, ReS2 doped with the non-noble TMs Mo and Cr showed excellent HER catalytic activities comparable with those of Pt-doped ReS2. Our findings will help to guide the future design of new HER catalysts based on TMDCs.

Direct imaging of the interaction between spin wave and transverse wall in magnetic nanostrip.

By micromagnetic simulations, the dynamical interaction between spin wave (SW) and a transverse wall (TW) in a magnetic nanostrip is studied. We find the dynamical interaction can be directly demonstrated by SW-induced TW oscillation, which can be obtained by calculating the total magnetic moment within the area of TW as a function of time. Two cases of the initial TW, in equilibrium state and in metastable state, are investigated and compared. Before SW reaches TW, the metastable TW oscillates naturally with a constant frequency, whereas the equilibrium TW does not oscillate. After SW acts on TW, both the metastable TW and the equilibrium TW will oscillate with a frequency that always equal to the frequency of the applied SW. The amplitude of the SW-induced TW oscillation for both the metastable case and the equilibrium case strongly depends on the frequency of the applied SW. Through tuning the frequency of the applied SW, we confirm that the natural oscillation of the metastable TW, which is independent of the applied SW, will not affect the amplitude of the SW-induced TW oscillation and the velocity of the TW motion in compare with those of the equilibrium TW. Interestingly, the frequency-response curves of the SW-induced TW oscillations display multiple resonance peaks. Moreover, we find the frequency-response curves of the SW-induced TW oscillation, SW reflection coefficient and TW velocity driven by SW share the same multiple-resonance property. It may suggest the SW-induced TW oscillation in the domain wall plays an important role in the SW-driven TW motion.

Integrating Semiconducting Catalyst of ReS2 Nanosheets into P-Silicon Photocathode for Enhanced Solar Water Reduction.

Loading electrocatalysts at the semiconductor-electrolyte interface is one of the promising strategies to develop photoelectrochemical water splitting cells. However, the assembly of compatible and synergistic heterojunction between the semiconductor and the selected catalyst remains challenging. Here, we report a hierarchical p-type silicon (p-Si)/ReS2 heterojunction photocathode fabricated through the uniform growth of vertically standing ReS2 nanosheets (NSs) on a planar p-Si substrate for the solar-driven hydrogen evolution reaction (HER). The laden ReS2 NSs not only serve as a high-activity HER catalyst but also render a suitable electronic band coupled with p-Si into a II-type heterojunction, which facilitates the photoinduced charge production, separation, and utilization. As a result, the assembled p-Si/ReS2 photocathode exhibits a 23-fold increased photocurrent density at 0 VRHE and a 35-fold enhanced photoconversion efficiency compared with the pure p-Si counterpart. The bifunctional ReS2 as a catalyst and a semiconductor enables multi-effects in improving light harvesting, charge separation, and catalytic kinetics, highlighting the potential of semiconducting catalysts integrated into solar water splitting devices.