Rigidly Axial O Coordination-Induced Spin Polarization on Single Ni-N4-C Site by MXene Coupling for Boosting Electrochemical CO2 Reduction to CO.

Regulating the spin states in transition-metal (TM)-based single-atom catalysts (SACs), such as the TM-Nx-C configurations, is crucial for improving the catalytic activity. However, the role of spin in single Ni atoms facilitating the electrochemical CO2 reduction reaction (CO2RR) has been largely overlooked. Using first-principles simulations, we investigated the electrocatalytic performance of Ni-N4-C SACs vertically stacked on the O-terminated MXene nanosheets for the CO2RR. The terminated O atoms on MXene axially interact with the Ni atom due to significant charge transfer between them. Unlike the pure Ni-N4 site, which lacks spin polarization, the newly formed Ni-N4O configuration breaks the spin degeneracy of Ni d orbitals, dramatically lifting the energy level of spin-down d orbitals relative to that of spin-up d orbitals. As a result, the d electrons of Ni in the two spin channels are rearranged, leading to large net spin moments of 1.4 µB. Compared to the Ni-N4 site, the partially filled minority-spin dz2 orbitals of Ni on Ni-N4O weaken the occupied d-π* orbitals between Ni and *COOH, significantly stabilizing the key intermediate. The detailed reaction mechanisms and energetics show that four MXenes, namely, Hf3C2, Zr3C2, Hf2C, and Zr2C, can induce a large spin on the Ni site, thereby improving catalytic activity for CO2 reduction to CO, with a lower onset potential of about -0.75 V vs SHE compared to pure Ni SACs (-1.17 V) according to the potential-constant model with an explicit solvent environment.

Photoelectrocatalytic Synthesis of Urea from Carbon Dioxide and Nitrate over a Cu2O Photocathode.

Transformation of carbon dioxide and nitrate ions into urea offers an attractive route for both nitrogen fertilizer production and environmental remediation. However, achieving this transformation under mild conditions remains challenging. Herein, we report an efficient photoelectrochemical method for urea synthesis by co-reduction of carbon dioxide and nitrate ion over a Cu2O photocathode, delivering urea formation rate of 29.71±2.20 µmol g-1 h-1 and Faradaic efficiency (FE) of 12.90±1.15 % at low external potential (-0.017 V vs. reversible hydrogen electrode). Experimental data combined with theoretical calculations suggest that the adsorbed CO* and NO2* species are the key intermediates, and associated C-N coupling is the rate-determining step. This work demonstrates that Cu2O is an efficient catalyst to drive co-reduction of CO2 and NO3 - to urea under light irradiation with low external potential, showing great opportunity of photoelectrocatalysis as a sustainable tool for value-added chemical synthesis.

Engineering Spin Polarization of the Surface-Adsorbed Fe Atom by Intercalating a Transition Metal Atom into the MoS2 Bilayer for Enhanced Nitrogen Reduction.

The precise control of spin states in transition metal (TM)-based single-atom catalysts (SACs) is crucial for advancing the functionality of electrocatalysts, yet it presents significant scientific challenges. Using density functional theory (DFT) calculations, we propose a novel mechanism to precisely modulate the spin state of the surface-adsorbed Fe atom on the MoS2 bilayer. This is achieved by strategically intercalating a TM atom into the interlayer space of the MoS2 bilayer. Our results show that these strategically intercalated TM atoms can induce a substantial interfacial charge polarization, thereby effectively controlling the charge transfer and spin polarization on the surface Fe site. In particular, by varying the identity of the intercalated TM atoms and their vacancy filling site, a continuous modulation of the spin states of the surface Fe site from low to medium to high can be achieved, which can be accurately described using descriptors composed of readily accessible intrinsic properties of materials. Using the electrochemical dinitrogen reduction reaction (eNRR) as a prototypical reaction, we discovered a universal volcano-like relation between the tuned spin and the catalytic activity of Fe-based SACs. This finding contrasts with the linear scaling relationships commonly seen in traditional studies and offers a robust new approach to modulating the activity of SACs through interfacial engineering.

Interplay between Defects and Short-Range Disorder Manipulating the Oxygen Evolution Reaction on a Layered Double Hydroxide Electrocatalyst.

Improving the efficiency of the oxygen evolution reaction (OER) is crucial for advancing sustainable and environmentally friendly hydrogen energy. Layered double hydroxides (LDHs) have emerged as promising electrocatalysts for the OER. However, a thorough understanding of the impact of structural disorder and defects on the catalytic activity of LDHs remains limited. In this work, a series of NiAl-LDH models are systematically constructed, and their OER performance is rigorously screened through theoretical density functional theory. The acquired results unequivocally reveal that the energy increase induced by structural disorder is effectively counteracted at the defect surface, indicating the coexistence of defects and disorder. Notably, it is ascertained that the simultaneous presence of defects and disorder synergistically augments the catalytic activity of LDHs in the context of the OER. These theoretical findings offer valuable insights into the design of highly efficient OER catalysts while also shedding light on the efficacy of LDH electrocatalysts.

Broad-spectrum activity of bulevirtide against clinical isolates of HDV and recombinant pan-genotypic combinations of HBV/HDV.

Background & Aims: Bulevirtide (BLV) is a small lipopeptide agent that specifically binds to the sodium taurocholate cotransporting polypeptide (NTCP) bile salt transporter and HBV/HDV receptor on the surface of human hepatocytes and inhibits HDV and HBV entry. As a satellite virus of HBV, HDV virions are formed after assembly of HDV RNA with the HBV envelope proteins (HBsAg). Because both viruses exist as eight different genotypes, this creates a potential for high diversity in the HBV/HDV combinations. To investigate the sensitivity of various combinations of HBV/HDV genotypes to BLV, clinical and laboratory strains were assessed. Methods: For the laboratory strains, the different envelopes from HBV genotypes A through H were combined with HDV genotypes 1-8 in cotransfection assays. Clinical plasma isolates were obtained from clinical studies and academic collaborations to maximise the diversity of HBV/HDV genotypes tested. Results: The mean BLV EC50 against HDV laboratory strains ranged from 0.44 to 0.64 nM. Regardless of HBV and HDV genotypes, the clinical isolates showed similar sensitivities to BLV with mean values that ranged from 0.2 to 0.73 nM. Conclusions: These data support the use of BLV in patients infected with any HBV/HDV genotypes. Impact and implications: This study describes the potent activity of BLV against multiple laboratory strains spanning all HBV/HDV A-H/1-8 genotype combinations and the most diverse collection of HDV clinical samples tested to date, including HBV/HDV genotype combinations less frequently observed in the clinic. Overall, all isolates and laboratory strains displayed similar in vitro nanomolar sensitivity to BLV. This broad-spectrum antiviral activity of BLV has direct implications on potential simplified treatment for any patient infected with HDV, regardless of genotype, and supports the new 2023 EASL Clinical Practice Guidelines on HDV that recommend antiviral treatment for all patients with CHD.

Elicitation of T-cell-derived IFN-γ-dependent immunity by highly conserved Plasmodium ovale curtisi Duffy binding protein domain region II (PocDBP-RII).

BACKGROUND: Infections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease has been underestimated. Plasmodium ovale curtisi Duffy binding protein domain region II (PocDBP-RII) is an essential ligand for reticulocyte recognition and host cell invasion by P. ovale curtisi. However, the genomic variation, antigenicity and immunogenicity of PocDBP-RII remain major knowledge gaps. METHODS: A total of 93 P. ovale curtisi samples were collected from migrant workers who returned to China from 17 countries in Africa between 2012 and 2016. The genetic polymorphism, natural selection and copy number variation (CNV) were investigated by sequencing and real-time PCR. The antigenicity and immunogenicity of the recombinant PocDBP-RII (rPocDBP-RII) protein were further examined, and the humoral and cellular responses of immunized mice were assessed using protein microarrays and flow cytometry. RESULTS: Efficiently expressed and purified rPocDBP-RII (39 kDa) was successfully used as an antigen for immunization in mice. The haplotype diversity (Hd) of PocDBP-RII gene was 0.105, and the nucleotide diversity index (π) was 0.00011. No increased copy number was found among the collected isolates of P. ovale curtisi. Furthermore, rPocDBP-RII induced persistent antigen-specific antibody production with a serum IgG antibody titer of 1: 16,000. IFN-γ-producing T cells, rather than IL-10-producing cells, were activated in response to the stimulation of rPocDBP-RII. Compared to PBS-immunized mice (negative control), there was a higher percentage of CD4+CD44highCD62L- T cells (effector memory T cells) and CD8+CD44highCD62L+ T cells (central memory T cells) in rPocDBP-RII­immunized mice. CONCLUSIONS: PocDBP-RII sequences were highly conserved in clinical isolates of P. ovale curtisi. rPocDBP-RII protein could mediate protective blood-stage immunity through IFN-γ-producing CD4+ and CD8+ T cells and memory T cells, in addition to inducing specific antibodies. Our results suggested that rPocDBP-RII protein has potential as a vaccine candidate to provide assessment and guidance for malaria control and elimination activities.

Gut microbial genetic variation modulates host lifespan, sleep, and motor performance.

Recent studies have shown that gut microorganisms can modulate host lifespan and activities, including sleep quality and motor performance. However, the role of gut microbial genetic variation in regulating host phenotypes remains unclear. In this study, we investigated the links between gut microbial genetic variation and host phenotypes using Saccharomyces cerevisiae and Drosophila melanogaster as research models. Our result suggested a novel role for peroxisome-related genes in yeast in regulating host lifespan and activities by modulating gut oxidative stress. Specifically, we found that deficiency in catalase A (CTA1) in yeast reduced both the sleep duration and lifespan of fruit flies significantly. Furthermore, our research also expanded our understanding of the relationship between sleep and longevity. Using a large sample size and excluding individual genetic background differences, we found that lifespan is associated with sleep duration, but not sleep fragmentation or motor performance. Overall, our study provides novel insights into the role of gut microbial genetic variation in regulating host phenotypes and offers potential new avenues for improving health and longevity.

Coexistence of Au single atoms and Au nanoparticles on NiAl-LDH for selective electrooxidation of benzyl alcohol to benzaldehyde.

Introducing different active sites into heterogeneous catalysts provides new prospects to address the challenges in single-atom catalysis. Herein, the Au single atoms together and the Au nanoparticles were loaded onto NiAl-LDH by a facile impregnation-reduction method for the first time, resulting in the formation of Au1+n-NiAl-LDH, in which abundant Au single atoms are located around the Au nanoparticles with ∼5 nm size. When applied in the electrocatalytic benzyl alcohol oxidation reaction (BAOR), the as-prepared Au1+n-NiAl-LDH exhibits a remarkable selectivity of 91% and 177.63 µmol for benzaldehyde in 5 hours, while in contrast examples using solely Au single atom loaded NiAl-LDH (Au1-NiAl-LDH) and solely Au nanoparticle loaded NiAl-LDH (Aun-NiAl-LDH) can only realize 87.36 µmol production (75% selectivity) and 48.90 µmol production (28% selectivity) of benzaldehyde, respectively. Such a dramatic difference can be attributed to the synergistic effects of Au single atoms and Au nanoparticles. DFT calculation results reveal that for Au1+n-NiAl-LDH, Au single atoms promote the dehydrogenation capacity of LDH laminates, while Au nanoparticles offer adsorption sites for the electrophilic attachment of benzyl alcohol.

Global trade networks bring targeted opportunity for energy-related CH4 emission mitigation.

Recent literature highlights the contributions the global energy sector has made to anthropogenic CH4 emissions, calling for immediate action. However, extant studies have failed to reveal the energy-related CH4 emissions induced by global trades of intermediate and final commodities or services. This paper traces fugitive CH4 emissions via global trade networks using the multi-regional input-output and complex network models. Results show that approximately four-fifths of global fugitive CH4 emissions in 2014 were associated with international trade, of which 83.07% and 16.93% were embodied in the intermediate and final trades, respectively. Japan, India, the USA, South Korea, and Germany were the world's five largest net importers of embodied fugitive CH4 emissions, while Indonesia, Russia, Nigeria, Qatar, and Iran were the five largest net exporters. Gas-related embodied emission transfers were the largest in both the intermediate and the final trade networks. The fugitive CH4 emissions embodied within the intermediate and final trade networks were all characterized by five trading communities. The virtual fugitive CH4 emission transfers via intermediate trade were largely determined by global energy trade patterns, especially the trade in regionally integrated crude oil and natural gas. Significant heterogeneity was revealed by the coexistence of numerous loosely linked economies and several hub economies (e.g., China, Germany, the USA, and South Africa). Interventions on the demand side of interregional and intraregional trade partners in different communities and hub economies will bring targeted opportunities for global energy-related CH4 emission reduction.

Tracing global N2O emission mitigation strategies through trade networks.

Nitrous oxide (N2O) is the third most potent greenhouse gas (GHG) and the most important ozone depleting substance. But how global N2O emissions are connected through the interwoven trade network remains unclear. This paper attempts to specifically trace anthropogenic N2O emissions via global trade networks using a multi-regional input-output model and a complex network model. Nearly one quarter of global N2O emissions can be linked to products traded internationally in 2014. The top 20 economies contribute to about 70% of the total embodied N2O emission flows. In terms of the trade embodied emissions classified by sources, cropland-, livestock-, chemistry-, and other industries-related embodied N2O emissions account for 41.9%, 31.2%, 19.9%, and 7.0%, respectively. Clustering structure of the global N2O flow network is revealed by the regional integration of 5 trading communities. Hub economies such as mainland China and the USA are collectors and distributors, and some emerging countries, such as Mexico, Brazil, India, and Russia, also exhibit dominance in different kinds of networks. This study selects the cattle sector to further verify that low production-side emission intensities and trade cooperation can lead to N2O emission reduction. In view of the impact of trade networks on global N2O emissions, achieving N2O emission reduction calls for vigorous international cooperation.