B18-Core EXAFS
|
Diamond Proposal Number(s):
[34632]
Abstract: Polychlorinated aromatic hydrocarbons (PCAHs) in flue gas seriously threaten the environment and human health, and Ru-based catalysts exhibit efficient oxidation property for PCAHs removal. However, the current Ru catalysts either have high Ru loading/non-stable structure or are developed empirically whilst lack of design mechanism. Herein, a robust Ru single atom catalyst (0.5 Ru1/TiO2) was designed based on metal-support interaction for o-DCB (o-dichlorobenzene, a typical PCAHs) degradation, and it revealed significantly better oxidation activity with T50 = 207.4 °C and T90 = 243.5 °C than its contrast with weak metal-support interaction (0.5 RuNP/TiO2, T50 = 247.4 °C, T90 > 300 °C). In addition, 0.5 Ru1/TiO2 exhibited much better chlorine resistance stability, maintaining >90% o-DCB conversion for 700 min versus∼70% on 0.5 RuNP/TiO2. The superior performance of 0.5 Ru1/TiO2 was attributed to its stronger metal-support interaction between Ru and TiO2, verified by H2-TPR, which offered higher active oxygen species (22.4%), more Lewis acid (0.675 mmol/g) and higher exposed Ru ratio (> 90.0%) than 0.5 RuNP/TiO2 (15.0%, 0.068 mmol/g, 28.6%, respectively). The above properties can not only enhance o-DCB adsorption/activation and weaken its Csingle bondCl bonds but also favor partial/deep oxidation and remove deposited chlorine on 0.5 Ru1/TiO2, proved by in situ FT-IR. Moreover, notable higher water resistance under different water vapor and applicability under varied pollutant concentration were observed on the robust Ru1/TiO2. This work reveals insightful function-property study on Ru single atom catalysts for PCAHs oxidative removal.
|
May 2026
|
|
I20-Scanning-X-ray spectroscopy (XAS/XES)
|
Diamond Proposal Number(s):
[31906, 39961]
Open Access
Abstract: Mercury (Hg) is a global environmental concern due to its microbial conversion to methylmercury (MeHg), a potent neurotoxin that bioaccumulates in food webs and poses risks to ecosystems and human health. Thiol functional groups (RSH) play an important role in controlling Hg(II) speciation and bio-uptake in methylating bacteria, yet the spatial distribution and density of these thiols within cells remain largely unknown. We isolated subcellular fractions of the Hg methylating bacterium Geobacter sulfurreducens in the exponential growth phase, and used Hg LIII-edge EXAFS (Extended X-ray Absorption Fine Structure) to quantify thiols in the extracellular medium, inner and outer membranes, periplasm and cytoplasm. The whole-cell thiol content was determined to be 1.3 × 10−10 μmol cell−1. The inner membrane contributed 7.1 × 10−11 (53%), the outer membrane 1.2 × 10−11 (9%), the periplasm 3.6 × 10−11 (27%) and the cytoplasm 1.5 × 10−11 μmol cell−1 (11%). The extracellular fraction contributed an additional 5.7 × 10−11 μmol cell−1, corresponding to 30% of the thiols of the cell culture. Local thiol density (thiols normalized to TOC in individual compartment, RSH/TOC, μmol g−1 C) was 36, 450, 140, 600 and 29 μmol g−1 C in the cytoplasm, inner membrane, periplasm, outer membrane and extracellular fractions, respectively. EXAFS analyses demonstrate Hg-thiolate coordination across all compartments, with Hg-O/N bonding and elemental Hg0 formed at higher Hg loadings. In the periplasm, Hg-disulfide and traces of β-HgS were detected. The high thiol density at the membranes, relative to other compartments, may imply they have an important role in the retention and internalization of Hg(II). Periplasmic thiols may modulate Hg(II) transfer between membranes, and cytoplasmic thiols may regulate the intracellular availability of Hg(II) for methylation. This work provides the first compartment-resolved quantification of thiol abundances and densities in a model Hg-methylating bacterium at subcellular level, offering a mechanistic framework for understanding the speciation, bioavailability, and subcellular transformation of Hg(II) with relevance for other soft metals (e.g., Cd, Pb, Zn, Ag, and Cu).
|
Feb 2026
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[34632]
Open Access
Abstract: Mitigating carbon emissions and plastic waste is a pressing societal challenge due to the disruptive environmental impact of incremental accumulation. A promising strategy to address both issues is coelectrolysis of CO2 and PET-plastic waste to high-value commodity chemicals. Here, we report electrocatalytic upcycling of polyethylene terephthalate (PET) plastic to formate and terephthalic acid using a cobalt-based metal–organic framework (Co-MOF-74). The electrocatalyst underwent oxidative restructuring to cobalt oxyhydroxide under operating conditions and exhibited near-unity faradaic efficiency (FE) for the ethylene glycol oxidation reaction (EGOR) to formate during short-term electrolysis. Notably, EGOR required 0.23 V lower potential compared to the conventional oxygen evolution reaction (OER) at a current density of 100 mA cm–2. When coupled with a CO2 reducing cathode, a maximum combined FE of 156% was achieved for formate (anode) and syngas (cathode) at a cell voltage (Ecell) of 1.6 V. Upon integration of the EGOR electrode in a CO2-fed flow cell, the coupled system required an Ecell of ∼2.3 V to operate at 75 mA cm–2. This work presents a promising integrated approach that offers a compelling solution for mitigating environmental pollution by enabling the electrochemical reforming of CO2 and plastic waste into valuable chemicals under cost-effective and energy-efficient conditions.
|
Jan 2026
|
|
B18-Core EXAFS
I18-Microfocus Spectroscopy
|
Swaroop
Chakraborty
,
Iuliia
Mikulska
,
Pankti
Dhumal
,
Nathan
Langford
,
Susan
Nehzati
,
Rhiannon
Boseley
,
Sang
Pham
,
Christian
Pfrang
,
Manpreet
Kaur
,
Eugenia
Valsami-Jones
,
Konstantin
Ignatyev
,
Dhruv
Menon
,
Superb K.
Misra
,
Iseult
Lynch
Diamond Proposal Number(s):
[33674, 35117, 35776, 40080, 40942]
Open Access
Abstract: Metal–organic frameworks (MOFs) hold immense potential for applications from separations to catalysis, yet their long-term behavior across real-world environments remains unclear. Here we introduce a hierarchical exposure framework that tracks the structural and chemical transformations in the archetypal zirconium MOF UiO-66 across sequential compartments─atmospheric gases, air, aqueous media and a biological host─and resolves how prior exposures condition or prime subsequent transformations. Using synchrotron-based spectroscopy, we find that oxidative/reactive gases leave the Zr-carboxylate nodes essentially intact, whereas exposure to environmentally relevant aqueous media initiates partial shifts in local Zr coordination and introduces oxygen into the pores─with transformation extent governed by the chemistry of the environmental matrices. Strikingly, acute exposure (24 h) to the water flea Daphnia magna drives profound framework degradation and respeciation to Zr hydroxide species. Microfocus XRF maps show that Zr is highly localized in the animal’s digestive tract, and region-specific XANES confirms uniform speciation across its tissues. Our findings establish a paradigm shifting cross-compartment transformation hierarchy in which biological processes can dominate the fate of stable MOFs even when abiotic exposures appear benign. Thus, organism-level biotransformation should be performed as a necessary part of environmental safety assessments and materials design.
|
Jan 2026
|
|
B18-Core EXAFS
|
Run
Ran
,
Haoliang
Huang
,
Qingqing
Chen
,
Fei
Lin
,
Zhipeng
Yu
,
Weifeng
Su
,
Chenyue
Zhang
,
Qingsen
Jia
,
Jingwei
Wang
,
Yang
Zhao
,
Kaiyang
Xu
,
Binwen
Zeng
,
Yaowen
Xu
,
Weimian
Zhang
,
Zhijian
Peng
,
Lifeng
Liu
Diamond Proposal Number(s):
[36104]
Abstract: Sulfur quantum dots (SQDs) represent an emerging class of metal-free, biocompatible luminescent nanomaterials, yet their synthesis remains challenged by harsh conditions, high energy consumption, and limited scalability. Herein, we report a highly value-added strategy coupling SQD synthesis with hydrogen production through sulfion (S2−) oxidation reaction (SOR) assisted alkaline-modified seawater electrolysis (SWE). Such coupling substantially lowers the energy demand for electrolysis and effectively circumvents the interfering chlorine evolution at the anode. An efficient and stable cobalt single-atom catalyst (Co-SAs-PNC) is developed to boost SOR, achieving a large current density of 500 mA cm−2 at 0.536 V vs. reversible hydrogen electrode in alkaline-modified natural seawater and operating stably for 116 h. A flow cell comprising Co-SAs-PNC as the anode catalyst and commercial Pt/C as the cathode catalyst requires only 1.01 V to reach 500 mA cm−2 and shows outstanding durability of >450 h. Besides valuable hydrogen generated at the cathode, the polysulfides electrochemically derived at the anode can be readily converted to multicolor photoluminescent SQDs. Comprehensive in situ/operando experiments and theoretical calculations elucidate the SOR mechanism at isolated Co sites. This work not only opens a new avenue for sustainable SQD production but also remarkably enhances the economic viability of the SWE technology.
|
Jan 2026
|
|
B18-Core EXAFS
I11-High Resolution Powder Diffraction
|
Zhaodong
Zhu
,
Xin
Lian
,
Xue
Han
,
Zi
Wang
,
Siyu
Zhou
,
Meng
He
,
Tianze
Zhou
,
Yuting
Chen
,
Mengtian
Fan
,
Wenyuan
Huang
,
Yuhang
Yang
,
Shaojun
Xu
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Jeff
Armstrong
,
Svemir
Rudic
,
William
Thornley
,
Evan
Tillotson
,
Daniel
Lee
,
Sarah
Haigh
,
Shiyu
Fu
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Sihai
Yang
Diamond Proposal Number(s):
[37887, 31729, 36450]
Abstract: Catalytic hydrodeoxygenation (HDO) is critical for bio-oil upgrading, yet the selective cleavage of stable C(sp2)–OH bonds in lignin-derived substrates under aqueous conditions remains a challenge. Here, we report a heteroatomic zeolite catalyst, RuFA/SAPO-34-Nb, featuring few-atom Ru clusters on a Nb(V)-modified SAPO-34 framework, which achieves highly efficient HDO of lignin-derived creosol (2-methoxy-4-methylphenol) in water. Under mild conditions (250 °C, 7 bar H2, 24 h), this catalyst delivers quantitative conversion of creosol to toluene (99.2% conversion, 99.6% selectivity), fully preserving the aromaticity of lignin-derived feedstocks─a key requirement for sustainable production of chemicals. Synchrotron X-ray diffraction, X-ray absorption spectroscopy, and inelastic neutron scattering, combined with theoretical modeling, elucidate the cooperative mechanism: the Nb(V) sites selectively cleave the strong C–O bonds, while the few-atom Ru cluster generates hydrogen species with an exceptionally low rotational barrier of 65 cm–1. This synergistic interaction enables the direct and selective HDO of C(sp2)–O bonds without saturation of the aromatic ring. This work establishes a promissing strategy for aqueous-phase HDO catalysis and provides a general approach for designing bimetallic zeolite catalysts to convert lignin-derived compounds to value-added aromatic chemicals, advancing sustainable biorefinery processes.
|
Jan 2026
|
|
B18-Core EXAFS
|
Abstract: The large-scale deployment of proton exchange membrane water electrolyzers (PEMWEs) is hindered by the scarcity and instability of iridium-based oxides (IrOx) catalysts during the acidic oxygen evolution reaction. Herein, we report a dynamic embedding strategy to construct highly stable and active low-iridium catalysts, which enables controlled incorporation of IrOx nanoclusters (NCs) into an amorphous TiOx overcoating supported on carbon nanotubes (IrOx/TiOx@CNT). Combined experimental and theoretical studies reveal that the dynamic embedding process enables coordinated growth kinetics, facilitating continuous anchoring of IrOx NCs within the flexible amorphous TiOx matrix. The resulting strong IrOx-TiOx interaction promotes significant electron transfer from TiOx to IrOx, thereby optimizing the adsorption energetics of oxygen intermediates and suppressing IrOx dissolution. The optimized catalyst achieves an exceptionally low overpotential of 258 mV at 10 mA cm−2 and outstanding durability in 0.5 m H2SO4. In PEMWE, the catalyst enables a cell voltage of 1.70 V at 1.0 A cm−2 with an ultralow Ir loading (0.3 mg cm−2), coupled with low energy consumption (45 kWh kg−1 H2) and hydrogen production cost (∼$0.9 kg−1 H2). This work underscores the pivotal role of amorphous overlayers in creating dynamically stable interfaces for advanced electrocatalysis.
|
Jan 2026
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[33569]
Open Access
Abstract: Green hydrogen production is limited by the thermodynamic energy requirement of water splitting. By decoupling the anodic and cathodic reactions using redox mediators, alternative feedstocks such as lignocellulosic biomass can yield comparable hydrogen purity with around half the total electrical energy input of conventional water electrolysis. Keggin-type heteropolyacids such as phosphomolybdic acid (H3PMo12O40) are increasingly of interest as mediators in decoupled electrochemical energy conversion applications, due to their reversible redox characteristics. However, the redox behaviour of heteropolyacids in aqueous solution during this process is still poorly understood. X-ray absorption spectroscopy (XAS) techniques offer the opportunity to directly probe changes in oxidation state and local structure of the mediator in-operando, allowing unprecedented insight into redox processes in a flow cell environment. Here, for the first time, we demonstrate operando XAS of reduced phosphomolybdic acid as it undergoes oxidation in a proton exchange membrane electrolyser with bespoke 3D-printed flow-fields. Changes in the time-resolved XAS were correlated to structural changes in the Keggin anion, which were closely related to the state-of-charge of the mediator, laying the groundwork for future studies of solution-phase Keggin-type heteropolyacid redox states. Furthermore, reduction of the phosphomolybdic acid via mild thermal digestion of either pure lignin or real agricultural biowaste is compared, in a step towards real-world applications. This work contributes significantly to the efficient and low-cost production of green hydrogen from waste biomass feedstocks, as well as providing insights into similar decoupled electrolysis processes.
|
Jan 2026
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[31395, 37736]
Abstract: Selenium-79, a radionuclide present in higher-activity radioactive wastes destined for deep geological disposal, is mobile under oxic conditions, where Se(IV) and Se(VI) dominate. Anoxic batch microcosm incubations were constructed containing Wyoming MX80 bentonite (a candidate buffer material in geological disposal) and artificial groundwater with or without steel coupons to represent canister materials. Se(VI)(aq) bioreduced and was removed by 7 days when lactate was added as an electron donor, after which sulfate reduction occurred. With H2 gas as the electron donor, Se(VI) bioreduction slowed, with complete removal at 14 days and minimal sulfate reduction thereafter. 16S rRNA gene sequencing highlighted the dominance of Anaerobacillus spp. (44% at 28 days) during Se(VI)-reduction, and in the lactate-amended systems, there was a subsequent enrichment in sulfate-reducing bacteria affiliated with Desulfosporosinus spp. (60% relative abundance at 84 days). Extended X-ray absorption fine structure (EXAFS) analyses identified monoclinic Se(0) as the bioreduction product after 28 days, but by 84 days this evolved to trigonal Se(0) in the absence of steel coupons or was further reduced to FeSe2 with steel present. The reduction of Se(VI)(aq) to poorly soluble Se(0)/FeSe2 mediated by indigenous bentonite microbial communities highlights their potential importance in promoting Se-79 retention during deep geological disposal.
|
Jan 2026
|
|
B18-Core EXAFS
|
Wenjie
Liu
,
Huibo
Zhao
,
Xianyue
Wu
,
Jianfeng
Wu
,
Lingjun
Chou
,
George
Dury
,
Wenting
Hu
,
Mikhail V.
Polynski
,
Arravind
Subramanian
,
Sergey M.
Kozlov
,
Wen
Liu
Diamond Proposal Number(s):
[34632]
Abstract: Understanding factors controlling product selectivity in CO2 hydrogenation remains a central research theme for catalytic CO2 utilization. Here, we report a composition-dependent selectivity anomaly in the In–Pd intermetallic series (viz., InPd2, InPd, In3Pd2), where In3Pd2 exhibits 100% CO selectivity via the reverse water–gas shift (RWGS) pathway, in sharp contrast to the high methanol selectivity achieved on other In-rich or Pd-rich metals or intermetallic compounds. Comprehensive characterization reveals that this anomaly arises from Pd enrichment on the surface of In3Pd2 IMC nanoparticles. The enriched Pd sites, modulated by In-to-Pd electron transfer, favor CO formation. In addition, the In-rich sites neighboring the Pd-rich islands facilitate rapid CO desorption. The resulting nanostructure on the surface of In3Pd2 IMCs renders an electronic interaction between In and Pd to promote CO formation and suppress C–H bond formation. This rationale is supported by both density functional theory (DFT) calculations and experimental evidence. These findings demonstrate that compositional control in intermetallic catalysts enables switchable CO2 hydrogenation selectivity and offers a rational approach to designing catalysts with tailored product distributions.
|
Jan 2026
|
|
