B18-Core EXAFS
E02-JEM ARM 300CF
|
Diamond Proposal Number(s):
[34632]
Open Access
Abstract: Conventional catalytic CO2 reduction into value-added products often encounters challenges such as high energy barriers and complex operational setups. Here, we introduce a sonocatalysis approach to CO2 reduction in water under ambient conditions. In an acoustic cavitation-induced high-energy local environment, the Cu nanoparticles incorporated on the ZnAl-layered double oxide create a favorable energy barrier for CO2 reduction in water, a CO production rate of 23.8 μmolCO g−1 h−1 with over 85% selectivity was achieved by ultrasonic irradiation of a CO2-saturated aqueous solution at room temperature. Furthermore, more acoustic cavitation was produced with 5% CO2 in argon dissolved in water, resulting in a higher CO productivity of 252.7 μmolCO g−1 h−1, 11 times larger than pure CO2. Hydrogen production also increased with acoustic cavitation, creating a syngas mixture with a CO to H2 ratio of 1.2 to 2.2. This approach produces a high sonochemical efficiency of 211.1 μmol kJ−1 g−1 L−1 for the ultrasound-driven fuel production from CO2 and water. These results highlight the use of cavitation to provide an alternative approach to CO2 conversion.
|
May 2025
|
|
B18-Core EXAFS
|
Mei
Han
,
Jieshu
Zhou
,
Shaojun
Xu
,
Honggang
Sun
,
Xin
Zi
,
Ning
Wang
,
Jingrui
Han
,
Weijia
Zhou
,
Haibin
Wang
,
Kangning
Liu
,
Emiliano
Cortés
,
Songhua
Chen
,
Mingchuan
Luo
,
Jieqiong
Shan
,
Min
Liu
,
Ziyun
Wang
,
Hongyan
Liang
,
Yongchang
Liu
Diamond Proposal Number(s):
[19850]
Abstract: Neutral water electrolysis faces challenges due to insufficient OH− supply, which leads to inefficient oxygen evolution reaction (OER). Constructing a localized OH−-enriched reaction environment is crucial for enhancing the neutral OER activity. Here, an integrated catalyst design aimed at optimizing the local reaction environment is presented to improve catalytic activity. Specifically, a high-curvature needle morphology is constructed to strengthen the local electric field, which induces localized OH− accumulation and mitigates OH− deficiency in the neutral electrolyte. Moreover, implanting Ag cores not only improves the conductivity and long-term stability of the NiCo-based catalytic shells but also enables Ag diffusion to dope the catalytic layer. At the atomic scale, Ag dopants modify the activity of oxygen ligands and the polarity of metal-oxygen (M─O) bonds within the symmetric spinel structure. This modification facilitates surface reconstruction, resulting in the formation of a distorted Ag-O-Ni/Co-OH network. The elongation of the Ni/Co−O bond generates an inhomogeneous charge distribution that optimizes water polarization and deprotonation, accelerating water dissociation and *OH formation. The multiscale catalyst design results in a unique interface featuring a high-curvature surface and atomic-scale polarized M─O networks, synergistically enhancing local *OH accumulation. Therefore, the optimal Ag@NiCo2O4 catalyst delivers a η10 = 295 mV in an H-cell electrolyzer and 2.1 V @1 A cm−2 in a membrane electrode assembly electrolyzer. This finding provides a practical design for OER electrocatalysts in neutral electrolytes and opens a new avenue for optimizing catalytic performance by integrating multiple strategies.
|
May 2025
|
|
I18-Microfocus Spectroscopy
|
Clare L.
Thorpe
,
Nick
Aldred
,
Stuart
Creasey-Gray
,
Martin C.
Stennett
,
Eperke A.
Rencz
,
Susan
Nehzati
,
Latham T.
Haigh
,
Garry
Manifold
,
Nishta
Vallo
,
Christoph
Lenting
,
Claire L.
Corkhill
,
Russell J.
Hand
Diamond Proposal Number(s):
[38045]
Open Access
Abstract: Glass ingots of lead silicate composition from the shipwreck of the Albion were studied to ascertain the chemistry and mineralogy of alteration products after exposure to seawater for 220 years. Alteration observed on natural samples was compared to that of the same glasses exposed to short-term, high temperature, laboratory dissolution tests in synthetic seawater and significant differences were observed. Alteration layers on natural samples were more chemically complex having sequestered high concentrations of elements present only at trace quantities in seawater. Electron microprobe analysis and microfocus x-ray absorption spectroscopy shows that P, most likely released by biological activity in the vicinity of the wreck, accumulated in naturally altered samples to form Pb–Ca-phosphate phases whilst Pb-sulphate phases formed in laboratory tests. Meanwhile Fe, present at < 0.3 wt % in the glass and ppb concentrations in seawater, accumulated to form Fe-silicates whilst Mg-silicates predominated in laboratory tests. Biologically induced corrosion of naturally altered samples was also considered. Experiments conducted to test barnacle settlement rates suggest that biotoxic elements within the glass, primarily Pb but potentially also Cu, Co and Ni deterred barnacle settlement. Despite this toxicity, some colonisation of the glass surface by both barnacles and bryozoan did occur and, whilst barnacles appeared to protect against chemical attack, bryozoan colonies caused increased cracking, possibly due stress created at the glass surface. Results highlight the challenges in recreating open, natural systems in laboratory settings and demonstrate that elements present at low concentrations can have a significant impact over long timescales.
|
May 2025
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[39179]
Open Access
Abstract: Developing photocatalysts that can efficiently utilize the full solar spectrum is a crucial step toward transforming sustainable energy solutions. Due to their light absorption limitations, most photo-responsive metal−organic frameworks (MOFs) are constrained to the ultraviolet (UV) and blue light regions. Expanding their absorp-tion to encompass the entire solar spectrum would unlock their full potential, greatly enhancing efficiency and applicability. Here, we report the design and synthesis of a series of highly stable boron-dipyrromethene (bodipy) based MOFs (BMOFs) by reacting dicar-boxyl-functionalized bodipy ligands with Zr-oxo clusters. Leveraging the acidity of the methyl groups on the bodipy backbone, we ex-panded the conjugation system through a solid-state condensation reaction with various aldehydes, achieving full-color absorption, thereby extending the band edge into the near-infrared (NIR) and infrared (IR) regions. These BMOFs demonstrated exceptional reac-tivity and recyclability in heterogeneous photocatalytic activities, including C−H bond activation of saturated aza-heterocycles and C−N bond cleavage of N,N-dimethylanilines to produce amides under visible light. Our findings highlight the transformative potential of BMOFs in photocatalysis, marking a significant leap forward in the design of advanced photocatalytic materials with tunable properties.
|
Apr 2025
|
|
B18-Core EXAFS
|
Abstract: As cost effective and sustainable materials for the recovery of platinum and palladium we have investigated the potential of sulfur-containing porous carbon materials. Utilising the naturally abundant sulfur-containing κ-carrageenan, or by doping K2SO4 into alternative polysaccharides (i.e. alginic acid), the Starbon process provides a sustainable route to high surface area mesoporous materials without the need for templates or activating agents. X-ray diffraction, elemental analysis and X-ray photoelectron spectroscopy were used to elucidate the development of sulfur chemistry during pyrolysis so that conditions could be optimised to yield materials with significant quantities of reduced organic sulfur chemistry, considered most promising for platinum group metal adsorption. The resulting materials were found to exhibit large capacities for Pd(II) (156 mg.g-1) and Pt(II) (246 mg.g-1) as well as selectivity over the other platinum group metals and the common contaminant ions Cu(II), Ni(II) and Co(II) in large excess. Pd(II) and Pt(II) could be removed by elution in thiourea and the material reused, suggesting excellent potential for the application of these materials to the recovery of platinum and palladium from low grade feeds. Analysis of adsorbed palladium using X-ray photoelectron and X-ray absorption spectroscopies provides evidence for coordination to organic sulfur-containing groups on the Starbon surface.
|
Apr 2025
|
|
B18-Core EXAFS
|
Yaowen
Xu
,
Kaiyang
Xu
,
Hao
Tan
,
Haoliang
Huang
,
Fei
Lin
,
Chenyue
Zhang
,
Jingwei
Wang
,
Run
Ran
,
Zhipeng
Yu
,
Sitaramanjaneya Mouli
Thalluri
,
Lijian
Meng
,
Dehua
Xiong
,
Lifeng
Liu
Diamond Proposal Number(s):
[36104]
Abstract: The development of efficient and durable electrocatalysts for the oxygen evolution reaction (OER) is critical to advancing anion exchange membrane water electrolysis (AEMWE) technology for sustainable hydrogen production. Herein, we report the synthesis of multimetallic NiCrFeMo layered double hydroxides (LDHs) via a facile microwave-assisted hydrothermal approach, engineered as high-performance OER catalysts for AEMWE operating at industrially relevant current densities. Advanced X-ray absorption spectroscopy (XAS) studies demonstrate that the interplay of Ni, Cr, Fe, and Mo tailors the electronic structure and coordination environment. Consequently, the NiCrFeMo LDHs exhibit remarkable OER performance, achieving overpotentials of 236 and 387 mV at 10 and 500 mA cm⁻², respectively, in 1.0 M KOH, as well as outstanding durability at 500 mA cm-2 for 1000 hours with negligible degradation. In-situ differential electrochemical mass spectroscopy (DEMS) and density functional theory (DFT) analyses reveal that the OER taking place on NiCrFeMo LDHs follows the adsorbate evolving mechanism, with minimal lattice oxygen involvement, contributing to the catalyst’s longevity. When integrated into a prototype AEM electrolyzer cell as the anode catalysts, the cell demonstrates a current density of 1 A cm⁻² at a relatively low voltage of 1.87 V and operates at 0.5 A cm-2 for 100 hours without decay, highlighting the potential of NiCrFeMo LDHs for practical applications. This work elucidates the synergistic effects of multimetallic compositions in LDHs, offering a strategy for designing cost-effective, high-efficiency OER catalysts to support green hydrogen production on scale.
|
Apr 2025
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[19850]
Abstract: It is well-established that tailoring the structural properties of nanoparticles, e.g., their size, shape, available active surface and interaction with metal oxide supports, imparts significant control on catalytic transformations. However, this often relies on the use of stabilizing (capping) agents. These capping agents, predominantly long chain or bulky polymers, are not benign and also influence the catalytic performance. In this study, we expand on the use of surfactant-controlled reaction pathways for the hydrogenation of furfural on Pd/TiO2. Furthermore, we demonstrate how solid-state NMR is able to study the surfactant-catalyst interaction and how these can be correlated to the selectivity profile for furfural hydrogenation.
|
Apr 2025
|
|
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
B18-Core EXAFS
I06-Nanoscience (XPEEM)
|
Abstract: The Sabatier reaction (CO2 methanation) represents a facile catalytic process to produce CH4 at relatively low temperatures and with high yields. Ni supported on ceria (Ni/CeO2) is widely recognised as an active catalyst due to the enriched Ni–CeOx interfacial sites. Here, the physicochemical properties of Ni/CeO2 are investigated by a variety of characterisation methods, including but not limited to X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and kerr-gated Raman to establish structure-activity relationships for CO2 methanation. In Chapter 3, the critical role of Ni availability, affected by both Ni particle size and potential encapsulation by reduced CeOx due to a strong metal-support interaction (SMSI), in forming interfacial sites, is highlighted. Chapter 4 examines the positive role of the surface oxygen vacancies (Ov) which was found to enhance Ni availability and MSI in Ni/CeO2 catalysts by creating a disordered and defective ceria film at the interface. This defect-dense Ni–CeOx interface altered the bonding mode between bidentate carbonates during the reaction. Results in chapter 5 evidenced the presence of Ni encapsulation, and confirmed the catalyst stability under at different activation temperatures and operating conditions. In Chapter 6, a two-dimensional (2D) Ni/CeO2 with single Ni NPs on CeO2 (100) crystal was explored using quasi in situ X-ray photoemission electron microscope (X-PEEM) and soft XAS. Detailed spatial analysis of Ni NPs and the surrounding Ce environment proposed the positive role of MSI for Ni reducibility and potential tuning methods. Also, the potential reconfigurations of Ni/CeO2 (e.g. oxidation/reduction and sintering/redispersion), were revealed under CO2 hydrogenation. In summary, the comprehensive research allowed us to better understand the role of Ov, Ni size and MSI in the formation of interfacial sites, and the correlation among these properties, essential for future designs of promising supported Ni catalysts for CO2 hydrogenation.
|
Apr 2025
|
|
B18-Core EXAFS
|
Pengwei
Wang
,
Peixi
Cong
,
Jiachen
Chen
,
Huaiyuan
Cao
,
Qi
Yue
,
Zixiao
Xue
,
Junji
Zhang
,
Long
Zhang
,
Robert S.
Weatherup
,
Jiabin
Cui
,
Jin
He
Diamond Proposal Number(s):
[31218]
Abstract: The confined synthesis of carbon dots (CDs) in solid matrixes is a promising avenue for developing new afterglow materials. Benefiting from the advantages of the sol–gel preparation of nanoporous glass, we report transparent glass-confined CDs with tunable afterglow luminescence. Switchable thermally-activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) of CDs were achieved by adjusting the sintering temperature and ion doping. Our findings reveal that with an increase in sintering temperature from 500 °C to 600 °C, the energy gap (ΔEST) of CD-nanoporous glass (NG) increased from 0.05 eV to 0.21 eV, while the lifetime increased from 329 ms to 548 ms, which is attributed to the enhanced carbonization degree of the CDs. Pb2+ doping is also shown to achieve switchable TADF and RTP of glass-confined CDs attributed to the alteration of interfacial interactions between the glass and confined CDs. This design concept introduces a new perspective for developing transparent afterglow materials for various unique phosphorescence applications.
|
Mar 2025
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[28356]
Open Access
Abstract: Developing sustainable and efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing energy storage technologies. This study explored the dual role of phosphorus as a dopant in carbon matrices and a key component in nickel phosphides (Ni2P and Ni12P5), synthesized using dopamine (PDA) and ammonium phosphate as eco-friendly precursors. The phase formation of nickel phosphides was found to be highly dependent on the P/PDA ratio (0.15, 0.3, 0.6, and 0.9), allowing for the selective synthesis of Ni2P or Ni12P5. Operando Raman spectroscopy revealed that both phases undergo surface transformation into nickel (oxy)hydroxide species under OER conditions, yet Ni2P-based catalysts demonstrated superior activity and long-term stability. This enhancement is attributed to efficient electron transfer at the dynamic Ni2P/NiOOH interface. Additionally, hollow nanostructures formed at intermediate P/PDA ratios (≤0.3) via the Kirkendall effect and Ostwald ripening contributed to an increased specific surface area and micropore volume, further improving the catalytic performance. Electrochemical impedance spectroscopy confirmed reduced interfacial resistance and enhanced charge transport. These findings offer new insights into the rational design of high-performance electrocatalysts and propose a green, tunable synthesis approach for advanced energy conversion applications.
|
Mar 2025
|
|
