Kuo-Wei Huang

Interfacial ion and water organization critically influence proton‐coupled electrochemical reactions, yet their coupled regulation under high‐rate CO ₂ electroreduction remains poorly understood. Here, we construct a mosaic‐and‐gap‐confined poly(dimethylsiloxane)‐modified Bi (Bi‐PDMS) interface that reorganizes the catalyst–electrolyte solvation environment. Atomistic simulations indicate altered near‐surface cation accessibility and a less persistent extended hydrogen‐bond environment, while slow‐growth proton‐transfer calculations show a substantially larger energetic penalty for selected extended proton‐delivery pathways than for local proton transfer to ^* OCHO. Operando spectroscopy and mass spectrometry measurements further reveal potential‐dependent interfacial water restructuring, suppressed hydrogen evolution, and enhanced formate‐related pathway response. Bi‐PDMS‐30 sustains ∼90% formate Faradaic efficiency (FE) at −0.2 A cm ^{− 2} for ∼200 h with substantially reduced surface‐deposit accumulation. Together, these results support differentiated interfacial proton delivery within a reorganized ion–water environment as a useful framework for selective and durable CO ₂ ‐to‐formate electrosynthesis.

Rationale: Lignocellulosic agricultural residues represent an enormous and largely untapped feedstock for second-generation biofuels, yet their structural recalcitrance remains the central bottleneck for cost-effective bioconversion. Conventional mesophilic enzymes lose much of their activity under the high-salinity, alkaline and thermally stressful conditions that define industrial biomass processing- a gap that microorganisms from naturally halo-alkaline ecosystems are well positioned to fill. Rice husk, generated in massive quantities as a by-product of rice milling across South Asia, remains an underutilized substrate whose silica-rich, lignin-shielded architecture makes it an appropriate and demanding test case for halotolerant biocatalysts. Methods: Three ecologically distinct saline habitats were sampled: Poovar Lake, a brackish mangrove estuary in Kerala (pH 6.92, salinity (chloride concentration) 1.90 g/L), Varkala Beach, a high-chloride concentration coastal site (pH 8.24, salinity (chloride concentration) 31.16 g/L), and Sanjay Lake, an anthropogenic inland lake in Delhi (pH 9.25, salinity (chloride concentration) 0.42 g/L). Using selective enrichment on halophilic media at 40 °C across a salinity range of 3–9% (w/v) NaCl, 29 halotolerant isolates were recovered and screened for xylanase, cellulase, lipase, amylase and protease activity using plate-based zone assays. The four most active cellulase- and xylanase-producing isolates, identified by 16S rRNA gene sequencing as Priestia flexa (XBL51), Bacillus proteolyticus (XBL61), Bacillus paralicheniformis (XBL66) and “ Vibrio neocaledonicus ” (XBL71), were then evaluated for their ability to hydrolyze alkaline-pretreated rice husk (1.5% (w/v) NaOH, 60 °C, 90 min) under saline-alkaline stress (4.5% (w/v) NaCl, pH 8.5, 40 °C). Growth kinetics and reducing sugar release were monitored over 6-days, and post-degradation structural changes in the biomass were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results: Alkaline pretreatment significantly disrupted the crystalline architecture of rice husk, reducing the crystallinity index (CrI) from 49.31% to 33.93%, thereby loosening the structure and substantially improving substrate accessibility for enzymatic attack. Among individual isolates, monoculture of XBL61 and XBL71, as well as XBL51 + XBL66 + XBL71 showed the strongest growth on pretreated rice husk as the sole carbon source. Reducing sugar release across the top-performing isolates and consortia ranged from 1.69 to 1.97 mg/g over the 6-day incubation. Monocultures XBL61 and XBL66 emerged as the most effective isolates, exhibiting sustained sugar production. Among the two-isolate consortium, XBL51 + XBL71 exhibited synergistic growth and hydrolysis activity. Post-incubation, XRD analysis showed that XBL61 alone raised the CrI marginally to 52.10%, suggesting reduction of amorphous regions, including non-cellulosic components such as hemicellulose and amorphous cellulose. By contrast, the XBL51 + XBL71 consortium reduced the CrI to 49.07%, reflecting more extensive and balanced structural deconstruction. SEM corroborated these findings, revealing a clear progression from the intact, tightly laminated surface of untreated biomass through the fissured, loosened layers of the pretreated material, to the deeply porous, honeycombed morphology left following consortium-mediated degradation. Conclusion: These results demonstrate that halotolerant bacteria isolated from contrasting saline habitats, particularly when used as rationally designed consortia, can effectively deconstruct alkaline-pretreated rice husk under conditions that would substantially inhibit conventional mesophilic cellulases. The inherent stress tolerance of these isolates makes them promising candidates for lignocellulosic biorefinery processes where elevated salinity and alkaline pH are unavoidable operational realities. Enzyme-level characterization and fermentation coupling of these isolates represent logical next steps toward translating these findings into scalable platforms for second-generation biofuel production.

The industrial synthesis of substitute natural gas via CO/CO ₂ methanation is severely hampered by the irreversible deactivation of nickel catalysts by trace sulfur impurities. Overcoming this challenge is difficult because the electronic properties that make nickel active also make it prone to strong sulfur bonding, creating a fundamental scaling relation. Here, we report a robust sulfur‐tolerant catalyst constructed by atomically dispersing ruthenium into a nickel lattice, which breaks this limitation. By leveraging the electronegativity difference between Ru and Ni, we induce a directed charge transfer that functionally decouples sulfur adsorption from the catalytic turnover. Combining in situ spectroscopy and density functional theory, we reveal that electron‐rich Ru single atoms act as deep thermodynamic traps for H ₂ S but energetically inhibit its dissociation into poisoning sulfide species. This decoy effect leaves the adjacent electron‐deficient Ni ensemble sites protected and free to drive the methanation reaction. Consequently, the catalyst exhibits exceptional stability in 10 ppm H ₂ S stream conditions that rapidly deactivate monometallic counterparts during both CO and CO ₂ methanation. This work demonstrates a generalizable electronic immunization strategy to design durable catalysts by spatially separating toxicant adsorption sites from active centers.

Solar salterns are environmentally stable yet biologically extreme ecosystems that serve as vital models for understanding and managing hypersaline environments, including industrial saline effluents. Despite their ecological and biotechnological significance, Indian solar salterns remain functionally underexplored. In this study, we integrated culture-dependent isolation with whole-metagenome sequencing to investigate microbial community assembly, functional specialization, and eco-technological potential across four geographically distinct Indian salterns. Physicochemical analyses revealed pronounced spatial variation in salinity, pH, and electrical conductivity, which together strongly structured microbial communities. Metagenomic sequencing generated between 4.84 and 8.68 Gb of raw data across individual site, yielding between 429,420 and 669,991 predicted genes in high-salinity locations. Taxonomic reconstruction demonstrated archaeal dominance at extreme salinity, particularly among Euryarchaeota, whereas comparatively moderate salinity sites supported more balanced bacterial–archaeal assemblages. Alpha diversity patterns indicated higher richness in Tamil Nadu and Rajasthan, while Gujarat exhibited reduced evenness consistent with environmental filtering. Culture-dependent approaches recovered 42 halophilic and polyextremophilic isolates, primarily affiliated with Halobacteriaceae and Bacillaceae, complementing the broad taxonomic detection of these lineages inferred from metagenomic data. Functional annotation revealed extensive enrichment of genes involved in ion transport, energy production, osmoprotectant biosynthesis, and DNA repair, reflecting an adaptive mechanism critical for survival in high-salinity industrial processes. Amino acid metabolism genes exceeded 25,000 hits in selected sites, and replication and repair genes reached 32,554 in Gujarat, indicating heightened stress-response activity. Secondary metabolite biosynthetic gene clusters, including pathways for novel antimicrobial peptides, terpene, ribosomally synthesized and post-translationally modified peptide-like, and type III polyketide synthase pathways, were widely distributed, offering new biological control mechanisms for environments impaired by stress. Antimicrobial resistance signatures were limited and unevenly distributed across sites. These findings demonstrate that salinity acts as a dominant ecological filter driving both taxonomic composition and functional specialization in Indian solar salterns. By linking environmental gradients to adaptive genomic traits, this study establishes a functional baseline for hypersaline ecosystems.

Integrated photoelectrochemical systems offer a promising pathway to produce value-added fuels from sunlight and abundant reagents. However, practical implementation remains challenging due to insufficient operating photovoltage, charge-carrier losses at the electrode–catalyst interface, and high catalytic overpotentials. Here, we fabricate a perovskite/silicon photoanode that combines a wide-bandgap metal-halide perovskite top junction with a double-textured crystalline silicon bottom junction to increase operating photovoltage. To minimize charge-transfer losses and promote catalyst adhesion, we integrate a photoanode with a graphite layer and further functionalize it with a low-overpotential Co-doped IrRu catalyst. The integrated photoanode achieves an open-circuit voltage of 1.86 V and a current density of 19 mA cm−2 at +1.23 VRHE. During unassisted two-electrode water splitting, the system achieves a solar-to-hydrogen efficiency of 16.06% and operates for 157 h. Extending to CO2-to-formate conversion, the two-electrode device reaches an applied-bias photon-to-current efficiency of 10.08% over 60 h. Our study highlights the potential of integrated photoelectrochemical systems for efficient solar-to-fuel conversion.

The overpotential in multielectron transfer heterogeneous electrocatalysis fundamentally arises from thermodynamic and kinetic disparities among elementary steps; however, deciphering coupled and competing steps has long remained a challenge. Here, we establish an electrochemical deconvolution paradigm based on key processes in electrocatalytic reactions, such as charge accumulation, electron/proton transfer, and intermediate evolution, to resolve competing elementary steps. Taking the oxygen evolution reaction as a prototypical reaction, we design a model catalyst featuring a precise isolated cation-anion vacancy pair and track the previously elusive electrochemical behavior of lattice oxygen by disentangling interference from adsorbed oxygen intermediates. Mechanistically, the lattice oxygen oxidation pathway originates from the spontaneous, nonelectrochemical deprotonation of replenished water molecules coordinated to unsaturated cation sites. Alternating current techniques further reveal that although lattice oxygen oxidation requires a higher potential than metal oxidation, it exhibits faster kinetics, providing insight into its superior catalytic activity. These findings establish a direct experimental correlation between the initial chemical state and the catalytic activity and prove surface-confined lattice oxygen cycling. Furthermore, expanding conventional potential-current analysis into a multidimensional framework enables disentanglement of thermodynamic and kinetic contributions of key elementary steps, thereby guiding the rational optimization of various complex multielectron transfer reactions.

We investigate the catalytic performance of PN ³ P pincer iridium dihydride complex in the dehydrogenation of cyclooctane to cyclooctene with conversion of tert -butylethylene (TBE) to 55% and TON up to 546.

The production of biofuels from renewable feedstocks to supply energy and alternative fuels has attracted significant attention. In particular, ethanol generated from renewable biomass is recognized as one of the greenest alternatives to gasoline. Herein we accomplished the upgrading of ethanol into butanol, as well as higher branched and linear chain alcohols up to C ₁₀ ─OH, in a single reactor under neat conditions catalyzed by an air‐ and moisture‐stable PN ³ P pincer iridium catalyst. The addition of potassium tert ‐butoxide (KO ^t Bu, 5.0 mol%) as a base, resulted in the highest turnover number (TON) up to 580, yielding 39% n ‐butanol with up to 95% selectivity. Under similar reaction conditions with a prolonged reaction time of 48 h, we achieved up to 60% ethanol conversion, resulting in a 37% yield of a mixture of linear and branched chain alcohols (C ₄₊ OH) along with 23% n ‐butanol.

The confinement of reactants within catalytic cavities is important for achieving efficient and selective chemical transformations. Macrocyclic organic covalent hosts, which mimic enzymatic environments, offer well-defined, tunable cavities capable of substrate accommodation. These robust and synthetically accessible hosts can be engineered into catalysts by functionalizing their rims, where substrate selectivity emerges from size- or shape-complementary binding. This positioning brings reactive sites into proximity with catalytic functional groups at the rims of covalent hosts, accelerating reactions. Cationic intermediates are pivotal in many chemical transformations, and stabilizing these reactive species within confined microenvironments could unlock unconventional selectivity for synthesizing high-value compounds. Despite this potential, leveraging the cavities of covalent hosts to stabilize and confine cationic intermediates for regioselective reactions remains underexplored. Here we report that the π-basic cavity of pillar[ n ]arenes can effectively stabilize bromiranium intermediates generated during olefin halogenation, confining them in a controlled microenvironment. This strategy overrides the intrinsic Markovnikov preference, enabling highly selective anti-Markovnikov halogenation. Furthermore, we extend this catalytic system to achieve size-selective anti-Markovnikov halogenation of olefins. This approach opens new pathways for selective transformations through the confinement of a cationic intermediate.