I11-High Resolution Powder Diffraction
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Jiaying
Mo
,
Lingling
Zhai
,
Alex W.
Robertson
,
Chiu C.
Tang
,
Sarah J.
Day
,
Simson
Wu
,
Lu
Chen
,
Tsz Woon Benedict
Lo
,
Molly Meng-Jung
Li
,
Shu Ping
Lau
,
Xin-Ping
Wu
,
Yiyang
Li
,
Shik Chi Edman
Tsang
Open Access
Abstract: Developing earth-abundant electrocatalysts that rival the commercial platinum/carbon catalyst for the hydrogen evolution reaction (HER) remains a central challenge in renewable-energy conversion. Here, we reveal an electrochemically induced, in situ phase transformation in a Ru-MgO catalyst that leads to true active material during operation. Under acidic HER conditions, nominal 20 wt.% Ru nanoparticles supported on polar MgO(111) nanocrystals undergo a topotactic hydrolysis to Ru-Mg(OH)2(001), generating an ordered hydroxide layer that serves as a highly conductive proton-hopping network. After activation, the catalyst delivers performance comparable to commercial Pt/C under identical conditions, matching the current density of −1.1 V and surpassing it by approximately 10% at −2.3 V. Operando synchrotron X-ray diffraction combined with ex situ characterization techniques directly captures this transformation, while density-functional theory calculations reveal that water-assisted Grotthuss proton transfer across the hydroxide requires only a 0.10 eV energy barrier. These findings establish electrochemically driven oxide-to-hydroxide conversion as a new design principle for creating low-Pt or Pt-free HER electrocatalysts with intrinsically fast proton transport.
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Apr 2026
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Shan
Dai
,
Xiangdi
Zeng
,
Benjamin J.
Moore
,
Yuxiang
Zhu
,
Yuhang
Yang
,
Zi
Wang
,
Luyan
Li
,
Te
Wang
,
Ivan
Da Silva
,
Luke
Keenan
,
Floriana
Tuna
,
Daniel
Lee
,
Sarah
Day
,
Lucy
Saunders
,
Martin
Schroeder
,
Sihai
Yang
Abstract: Metal–organic framework (MOF) materials share some common features with metalloenzymes including site-isolated metal centers that template dynamic substrate activation within a functionalized cavity or pocket. We report the light-induced reversible binding of CO2 in a cerium-based MOF, Ce-UiO-66-NH2, incorporating an amino functionalized linker, which enables photoreduction of CO2 to CO in H2O without using sacrificial agents. A production rate for CO of 126 μmol·g–1·h–1 with 100% selectivity is observed, outperforming its non-amine analogue (Ce-UiO-66) and benchmark catalysts reported to date. In situ infrared, X-ray absorption, electron paramagnetic resonance and transient absorption spectroscopy reveal that photoexcitation induces a ligand-to-metal charge transfer to generate transient open Ce(III) sites that bind CO2 in a μ-(η1-O)(η1-C) binding mode. This binding is reversible and activates CO2 for subsequent photoreduction to CO. This work will promote the design of photocatalysts capable of synthesizing fuels from CO2.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[34853]
Open Access
Abstract: Liquid-assisted grinding (LAG) is a commonly used mechanochemical procedure, especially for polymorphic conversions. However, it is not understood what effect liquid additives actually have in driving mechanochemical polymorphic conversions, precluding our ability to control solid form transformations under mechanochemical conditions. We here present a time-resolved in situ (TRIS) synchrotron powder X-ray diffraction (PXRD) monitoring strategy that can track, with few-nanometer resolution, the evolution of crystallite size under liquid-assisted ball milling conditions. We apply this method to investigate the influence of liquid additives on the polymorphic conversion of the 1:1 cocrystal of theophylline and benzamide, with particular focus on the role that crystallite size plays in driving ball milling-induced polymorphic transformations. We found that the crystallite sizes achieved by ball milling are highly sensitive to the amount of liquid added to the reaction mixture. Liquid additives generally lead to larger crystallite sizes as compared with the neat grinding (NG) protocol, with our findings indicating that crystallite size reduction is not the main factor that causes polymorph conversion under liquid-assisted grinding conditions. The data presented clearly suggest the presence of an induction period before phase transformation begins with a minimum value in the crystallite size of the starting polymorph, marking the end of that induction period.
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Feb 2026
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Open Access
Abstract: The incorporation of light-element dopants into monometallic nanoparticle catalysts enables precise modulation of their electronic structures, thereby tailoring catalytic performance. However, despite the widespread use and general understanding of such systems, fundamental aspects of dopant–framework interactions and solid-solution behavior in light-element-doped metal nanoparticles remain incompletely characterized. Here, using a one-step synthesis of lithiated palladium (Pd) nanoparticles formed by an in situ lithiation process with lithium (Li) acetate, we investigate the temperature-dependent phase behavior of the Pd–Li solid solution by variable-temperature synchrotron powder X-ray diffraction (VT-SPXRD). In situ thermal Bragg diffraction studies reveal unexpected delithiation dynamics and phase complexity in the metastable PdLi intermetallic compound, including previously unreported temperature-dependent lithium migration and site-occupancy redistribution. Remarkably, we demonstrate that interstitial lithium doping enhances thermal stability from 150 °C to over 400 °C, with higher lithium loadings (0.5–1.5 eq) maintaining structural integrity up to 515 °C. This unexpected stabilization, attributed to nanoparticle encapsulation effects, provides fundamental insight into light-element doping mechanisms in metallic nanoparticles and paves the way for the rational design of electronically tuned nanocatalysts.
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Jan 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[34800]
Open Access
Abstract: Layered crystal structures are commonly found across organic and inorganic material systems. When in-plane atomic arrangement remains (nearly) identical, a stacking variation of these layers may result in twinning, planar disorder, or polytypes, a form of polymorphism derived from altering stacking sequences. In this work, we use multi-dimensional electron diffraction (ED) modalities to explore the microstructure of xanthine, an archetypal purine base with a layered crystal structure. Firstly, we identify and characterise the twin operator relating domains of Form I xanthine. We then solve the structure of a new xanthine polymorph, revealing that it is a polytype of Form I. Finally, interfaces between twin and polytype domains are visualised, whilst streaking in the diffraction patterns reveals the presence of planar disorder. Given these observations in the xanthine system, this work suggests that disorder on the nanoscale may be a commonly occurring phenomenon in layered organic molecular crystals.
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Nov 2025
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
B18-Core EXAFS
E02-JEM ARM 300CF
I11-High Resolution Powder Diffraction
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Mengqi
Duan
,
Shuai
Guo
,
Wentian
Niu
,
Hangjuan
Ren
,
Thomas
Dittrich
,
Dongpei
Ye
,
Lucy
Saunders
,
Sarah
Day
,
Veronica
Celorrio
,
Diego
Gianolio
,
Peixi
Cong
,
Robert S.
Weatherup
,
Robert
Taylor
,
Songhua
Cai
,
Yiyang
Li
,
Shik Chi Edman
Tsang
Diamond Proposal Number(s):
[35749, 35750, 35961, 37117]
Open Access
Abstract: Two-dimensional layered perovskite oxides have emerged as promising photocatalysts for solar-driven hydrogen evolution. Although doping has been widely employed to enhance photocatalytic performance, its role in modulating the electronic structure and the local chemical environment of these materials remains poorly understood. Here in this study, we investigate the codoping of Rh and La into exfoliated nanosheets of the Dion–Jacobson perovskite KCa2Nb3O10 to enhance photocatalytic hydrogen evolution reaction (HER) activity. A substantial increase in H2 evolution rate, from 12.3 to 69.0 μmol h–1, was achieved at an optimal doping level of 0.2 wt % Rh and 1.3 wt % La. Comprehensive structural and spectroscopic analyses, including synchrotron techniques and high-resolution microscopy, revealed that Rh3+ substitutes Nb5+ to introduce shallow 4d acceptor states that mediate charge separation, while La3+ substitutes Ca2+, compensates for aliovalent charge imbalance, and modulates local lattice distortions and oxygen vacancy formation. This codoping strategy enhances charge carrier lifetime and separation efficiency through a trap-mediated mechanism. The observed volcano-shaped activity trend highlights a narrow compositional window, where electronic and structural factors are optimally balanced. These findings establish a mechanistic foundation for defect engineering in layered perovskites and offer a pathway for the rational design of photocatalysts.
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Oct 2025
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[11854]
Open Access
Abstract: Organic molecules formed within interstellar dust grain ice mantles may have contributed to the pre-biogenic organic inventory of the early Earth. Their ability to remain on the grain following mantle sublimation is likely to have been an important factor. Glycine, alanine, glutamic acid and aspartic acid were deposited on hydrogenated and dehydrogenated amorphous MgSiO3 particles and characterised by infrared spectroscopy and synchrotron X-ray powder diffraction. In situ synchrotron X-ray powder diffraction was subsequently used to monitor the loss of the amino acids from the silicates as a function of temperature. Only glycine and alanine were found to deposit on the amorphous silicate particles, evidenced by characteristic infrared bands and diffraction features. Glycine deposited as mixed phases, while D- and L-alanine deposited as single phases. A number of peptide and other phases of astronomical and astrobiological interest were also observed. Glycine was lost from the silicate at temperatures below the melting/degradation temperature of pure glycine, with ∼15 ○C difference between the hydrogenated and dehydrogenated silicates. Alanine survived to temperatures well above its melting point, but with clear temperature differences between L- and D- forms. Not all amino acids that potentially form under interstellar conditions appear able to transfer to bare silicate surfaces during ice mantle loss under warm early solar nebula/disk conditions. This could point to a possible astromineralogical selection mechanism that may have influenced the specific species, their relative proportion and therefore the contributions that pre-solar organics delivered by pre-solar dust may have made to the Earth’s original organic inventory.
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Sep 2025
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Lucy
Costley-Wood
,
Nicolás
Flores-González
,
Claire
Wilson
,
Paul
Thompson
,
Sarah
Day
,
Veronica
Celorrio
,
Donato
Decarolis
,
Ruby
Morris
,
Manfred E.
Schuster
,
Huw
Marchbank
,
Timothy I.
Hyde
,
Amy
Kolpin
,
Dave
Thompsett
,
Emma K.
Gibson
Diamond Proposal Number(s):
[29993, 29695, 19850]
Open Access
Abstract: The impact of rare-earth (RE) doping in ceria-zirconia─critical for enhancing thermal stability and optimizing redox properties─on surface palladium (Pd) behavior has been investigated. RE doping was found to weaken metal–support interactions, leading to increased Pd mobility, with notable effects on oxygen storage capacity and light-off performance under model exhaust conditions. The mobility and redox characteristics of Pd were assessed through in situ thermal experiments using X-ray absorption spectroscopy at the Pd K-edge and synchrotron powder diffraction. Complementary Ce K-edge EXAFS and Rietveld refinements confirmed the structure and composition of the doped ceria-zirconia material. Deactivation studies and lifetime prediction are essential for commercial catalysts, particularly for three-way catalysts (TWCs) designed for decade-long operation. To probe long-term stability, in situ thermal treatments were conducted to induce separation of the metastable ceria–zirconia solid solution. These accelerated thermal aging treatments were then compared with a prolonged, seven week aging protocol, and regular in situ synchrotron PXRD measurements provided insights into the phase separation process. The influence of thermal aging on metal–support interactions was further assessed through catalytic performance testing.
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Aug 2025
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B18-Core EXAFS
B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Boya
Tang
,
David
Brooks
,
Meng
He
,
Yinlin
Chen
,
Zhaozhao
Hu
,
Xue
Han
,
Jiangnan
Li
,
Siyu
Zhao
,
Jiarui
Fan
,
Yukun
Ye
,
Ivan
Da Silva
,
Cheng
Li
,
Zi
Wang
,
Lutong
Shan
,
Bing
Han
,
Weiyao
Li
,
Daniil
Polyukhov
,
Bing
An
,
Catherine
Dejoie
,
Martin
Wilding
,
Shaojun
Xu
,
Meredydd
Kippax-Jones
,
Zhaodong
Zhu
,
Yujie
Ma
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Sarah J.
Day
,
Stephen P.
Thompson
,
Mark D.
Frogley
,
Louise S.
Natrajan
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[37900, 37887, 36450]
Abstract: Photocatalytic synthesis of hydrogen peroxide (H2O2) from oxygen (O2) is a challenging process. Metal–organic framework (MOF) materials are emerging photocatalysts with potential tunable light absorption properties. Herein, we report a rhenium (Re) modified Zr-based MOF, Re10-MFM-67, in which active Re sites are incorporated into MFM-67 by partial replacement of 9,9′-bianthracene-10,10′-dicarboxylic acid (H2L1) with a [(H2L2)ReI(CO)3Cl] (H2L2 = 2,2′-bipyridine-5,5′-dicarboxylic acid) moiety. Re10-MFM-67 (10 refers to the molar percentage content of Re complex within the material) exhibits broadband light absorption with an exceptional rate of formation of H2O2 from O2 of 8.50 mmol gcat–1 h–1 and a record turnover frequency (TOF) of 28.7 h–1 under visible light irradiation (λ > 400 nm). Synchrotron powder X-ray diffraction (SPXRD) and neutron powder diffraction (NPD) confirm the structure of Re10-MFM-67, and together with extended X-ray absorption fine structure (EXAFS) analysis establish the coordination environment and binding of the [ReI(CO)3Cl] moiety within the framework structure. In situ electron paramagnetic resonance (EPR) spectroscopy suggests that photocatalytic H2O2 generation on Re10-MFM-67 occurs via a two-step oxygen reduction reaction (ORR) pathway with the superoxide anion formed as an intermediate. This study promotes the design of MOF-based photocatalysts with conjugated ligands for efficient photosynthesis.
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Jul 2025
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I11-High Resolution Powder Diffraction
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Jeremy P.
Lowen
,
Tharigopala V.
Beatriceveena
,
Joshua W.
Makepeace
,
Teresa
Insinna
,
Mark P.
Stockham
,
Bo
Dong
,
Sarah J,
Day
,
Clare P.
Grey
,
Emma
Kendrick
,
Peter R.
Slater
,
Paul A.
Anderson
Diamond Proposal Number(s):
[35016]
Open Access
Abstract: All-solid-state batteries utilising a Li-metal anode have long promised to be the next-generation of high-performance energy storage device, with a step-change in energy density, cycling stability and cell safety touted as potential advantages compared to conventional Li-ion battery cells. A key to enabling this technology is the development of solid-state electrolytes with the elusive combination of high ionic conductivity, wide electrochemical stability and the ability to form a conductive and stable interface with Li metal. Presently, oxide and sulfide-based materials, particularly garnet and argyrodite-type structures, have proved most promising for this application. However, these still suffer from a number of challenges, including resistive lithium metal interfaces, poor lithium dendrite suppression (at high current density) and low voltage stability. Here we report the first application of lithium imide, an antifluorite-structured material, as a solid electrolyte in a Li-metal battery. Low-temperature synthesis of lithium imide produces promising Li-ion conductivity, reaching > 1 mS cm-1 at 30 ˚C using a modest post-synthetic mechanochemical treatment, as well as displaying at least 5 V stability vs Li+/Li. In situ electrochemical operation of lithium imide with Li-metal electrodes reveals an apparent 1000-fold increase in its measured conductivity, whilst appearing to remain an electronic insulator. It is postulated that stoichiometry variation at the grain boundary may contribute to this conductivity improvement. Furthermore, the material is shown to possess impressive resistance to hard shorting under high current density conditions (70 mA cm-2) as well as the ability to operate in Li-metal battery cells. These results not only highlight the promising performance of lithium imide, but also its potential to be the basis for a new family of antifluorite based solid electrolytes.
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Apr 2025
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