B18-Core EXAFS
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Fei
Guo
,
Manxi
Gong
,
Longxiang
Liu
,
Bochen
Li
,
Ruwei
Chen
,
Mengjun
Gong
,
Wei
Zong
,
Jianuo
Chen
,
Qi
Li
,
Jing
Li
,
Yunpeng
Zhong
,
Zeyi
Zhang
,
Jianrui
Feng
,
Rhodri
Jervis
,
Guanjie
He
Diamond Proposal Number(s):
[34632]
Open Access
Abstract: Platinum–transition metal (PtM) alloys are among the most promising oxygen reduction reaction (ORR) catalysts, yet their practical deployment in proton-exchange membrane fuel cells (PEMFCs) is hindered by transition-metal dissolution, particle coarsening, and insufficient durability. Moreover, conventional alloying or intermetallic ordering strategies often aggravate these issues by inducing severe nanoparticle aggregation and instability. Here we report a controllable alloying–dealloying strategy to construct PtNi nanoparticles confined in an N-doped carbon framework (Pt1Ni1-x@Nix_NC). Ammonia-assisted dealloying produces a Pt-rich shell with an alloyed core, while the N-doped carbon anchors the released Ni atoms form Ni–N/C moieties, thereby suppressing agglomeration and strengthening metal–support interactions. This coordination–support coupling optimizes Pt 5d orbital occupation, weakens oxygen adsorption, and accelerates ORR kinetics. Consequently, Pt1Ni1-x@Nix_NC exhibits a half-wave potential of 0.932 V and an ultrahigh mass activity of 2.028 A mgPt−1, which is 8.75-fold higher than commercial Pt/C and among the best values reported to date for PtNi-based catalysts. Remarkably, it shows only a 6 mV half-wave potential loss after 30,000 cycles, demonstrating exceptional durability. In PEMFCs, the fuel cell delivers 975 mW cm−2 peak power density and retains 91.9% of initial performance, underscoring a generalizable approach for designing durable, high-performance low-PGM catalysts for next generation PEMFCs.
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Feb 2026
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B18-Core EXAFS
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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.
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Jan 2026
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[35875]
Open Access
Abstract: Aqueous zinc metal batteries (AZMBs) face significant challenges in achieving reversibility and cycling stability, primarily due to hydrogen evolution reactions (HER) and zinc dendrite growth. In this study, by employing carefully designed cells that approximate the structural characteristics of practical batteries, we revisit this widely held view through in-operando X-ray radiography to examine zinc dendrite formation and HER under near-practical operating conditions. While conventional understanding emphasizes the severity of these processes, our findings suggest that zinc dendrites and HER are noticeably less pronounced in dense, real-operation configurations compared to modified cells, possibly due to a more uniform electric field and the suppression of triple-phase boundaries. This study indicates that other components, such as degradation at the cathode current collector interface and configuration mismatches within the full cell, may also represent important barriers to the practical application of AZMBs, particularly during the early stages of electrodeposition.
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Dec 2025
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B18-Core EXAFS
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Yu
Zhu
,
Fei
Guo
,
Qiliang
Wei
,
Feiyan
Lai
,
Runzhe
Chen
,
Jianing
Guo
,
Manxi
Gong
,
Shunqiang
Zhang
,
Zichen
Wang
,
Jun
Zhong
,
Guanjie
He
,
Niancai
Cheng
Diamond Proposal Number(s):
[34632]
Open Access
Abstract: The oxygen spillover on the metal/oxide electrocatalysts interface acts as an essential role in promoting the oxygen evolution reaction (OER) for proton exchange membrane water electrolyzers (PEMWEs). However, oxygen spillover mechanisms and corresponding regulatory strategies are still unclear for addressing slow OH-migration kinetics. Herein, an interface is constructed between Iridium (Ir) and Niobium (Nb)-doped Titanium oxide (TiO2) with abundant oxygen vacancies area by plasma processing, enabling oxygen spillover from the metal Ir to supports. The optimized Ir/Nb-doped TiO2 with a significant OER activity (η = 253 mV) and durability in acids compared to commercial IrO2. In situ experiments combined with theoretical computations reveal the presence of interfacial oxygen vacancies not only regulates the Ir structure toward boosted activity but also constructs a directional spillover pathway from Ir to interfacial oxygen vacancies area and then TiO2 via the OH*-filling route, which strikingly mitigates the OH* migration barriers. In addition, the optimized Ir/Nb-doped TiO2 exhibits excellent performance (1.69 V/1.0 A cm−2@80 °C) and long-term stability (≈500 h@1.0 A cm−2) with practical potential in PEMWEs. This work provides a unique insight into the role of oxygen spillover, paving the way for designing Ir-based catalysts for PEMWEs.
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Jan 2025
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I14-Hard X-ray Nanoprobe
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Ruwei
Chen
,
Yunpeng
Zhong
,
Peie
Jiang
,
Hao
Tang
,
Fei
Guo
,
Yuhang
Dai
,
Jie
Chen
,
Jingyi
Wang
,
Jiyang
Liu
,
Song
Wei
,
Wei
Zhang
,
Wei
Zong
,
Fangjia
Zhao
,
Jichao
Zhang
,
Zhengxiao
Guo
,
Xiaohui
Wang
,
Guanjie
He
Diamond Proposal Number(s):
[36785]
Open Access
Abstract: Long-standing challenges including notorious side reactions at the Zn anode, low Zn anode utilization, and rapid cathode degradation at low current densities hinder the advancement of aqueous zinc-ion batteries (AZIBs). Inspired by the critical role of capping agents in nanomaterials synthesis and bulk crystal growth, a series of capping agents are employed to demonstrate their applicability in AZIBs. Here, it is shown that the preferential adsorption of capping agents on different Zn crystal planes, coordination between capping agents and Zn2+ ions, and interactions with metal oxide cathodes enable preferred Zn (002) deposition, water-deficient Zn2+ ion solvation structure, and a dynamic cathode-electrolyte interface. Benefiting from the multi-functional role of capping agents, dendrite-free Zn plating and stripping with an improved Coulombic efficiency of 99.2% and enhanced long-term cycling stability are realized. Remarkable capacity retention of 91% is achieved for cathodes after more than 500 cycles under a low current density of 200 mA g−1, marking one of the best cycling stabilities to date. This work provides a proof-of-concept of capping agents in manipulating electrochemical behaviors, which should inspire and pave a new avenue of research to address the challenges in practical energy storage beyond AZIBs.
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Jan 2025
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B18-Core EXAFS
E02-JEM ARM 300CF
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Longxiang
Liu
,
Liqun
Kang
,
Jianrui
Feng
,
David G.
Hopkinson
,
Christopher S.
Allen
,
Yeshu
Tan
,
Hao
Gu
,
Iuliia
Mikulska
,
Veronica
Celorrio
,
Diego
Gianolio
,
Tianlei
Wang
,
Liquan
Zhang
,
Kaiqi
Li
,
Jichao
Zhang
,
Jiexin
Zhu
,
Georg
Held
,
Pilar
Ferrer
,
David
Grinter
,
June
Callison
,
Martin
Wilding
,
Sining
Chen
,
Ivan
Parkin
,
Guanjie
He
Diamond Proposal Number(s):
[30614, 32058, 32035, 32117, 33466, 29271]
Open Access
Abstract: Electrochemical hydrogen peroxide (H2O2) production (EHPP) via a two-electron oxygen reduction reaction (2e- ORR) provides a promising alternative to replace the energy-intensive anthraquinone process. M-N-C electrocatalysts, which consist of atomically dispersed transition metals and nitrogen-doped carbon, have demonstrated considerable EHPP efficiency. However, their full potential, particularly regarding the correlation between structural configurations and performances in neutral media, remains underexplored. Herein, a series of ultralow metal-loading M-N-C electrocatalysts are synthesized and investigated for the EHPP process in the neutral electrolyte. CoNCB material with the asymmetric Co-C/N/O configuration exhibits the highest EHPP activity and selectivity among various as-prepared M-N-C electrocatalyst, with an outstanding mass activity (6.1 × 105 A gCo−1 at 0.5 V vs. RHE), and a high practical H2O2 production rate (4.72 mol gcatalyst−1 h−1 cm−2). Compared with the popularly recognized square-planar symmetric Co-N4 configuration, the superiority of asymmetric Co-C/N/O configurations is elucidated by X-ray absorption fine structure spectroscopy analysis and computational studies.
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May 2024
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B18-Core EXAFS
E01-JEM ARM 200CF
E02-JEM ARM 300CF
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Fangjia
Zhao
,
Jianwei
Li
,
Arunabhiram
Chutia
,
Longxiang
Liu
,
Liqun
Kang
,
Feili
Lai
,
Haobo
Dong
,
Xuan
Gao
,
Yeshu
Tan
,
Tianxi
Liu
,
Ivan P.
Parkin
,
Guanjie
He
Diamond Proposal Number(s):
[32905, 29340, 32058]
Open Access
Abstract: The design and synthesis of manganese oxide-based materials with high-rate performance and long cycle life is a major challenge for aqueous zinc-ion batteries (AZIBs). This research reports the presence of a synergistic collaboration between vacancies, lattice water and nickel ions on enhancing the hydrated protons hopping via the Grotthuss mechanism for high-performance zinc ion batteries. The Grotthuss mechanism allows for the efficient transfer of a proton charge without the actual movement of the molecule over long distances, resulting in high ionic conductivity. NiMn3O7·3H2O achieves a capacity of 318 mA h g−1 under 200 mA g−1 and 121 mA h g−1 under 5 A g−1 with a retention of 91% after 4000 cycles. The relationship between the remarkable performance and Grotthuss topochemistry is investigated using techniques including synchrotron X-ray absorption spectroscopy and density functional theory. Protons prefer to bond with O2− ions on the Mn–O layer, and proton transfer is favoured in the presence of vacancies. The continuous hopping of protons within the host material induces periodic, temporary local structural changes in the lattice. This dynamic behaviour alters the energy barriers for ions intercalation and deintercalation. Nickel ions facilitate the ongoing mobility of hydrated protons via Grotthuss hopping by preserving the system's electrical neutrality, which counterbalances the dynamic changes caused by proton migration. This study provides insight into the Grotthuss conduction mechanism for the development of high-performance cathode materials in AZIBs.
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Jan 2024
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E02-JEM ARM 300CF
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Jichao
Zhang
,
Jiexin
Zhu
,
Liqun
Kang
,
Qing
Zhang
,
Longxiang
Liu
,
Fei
Guo
,
Kaiqi
Li
,
Jianrui
Feng
,
Lixue
Xia
,
Lei
Lv
,
Wei
Zong
,
Paul R.
Shearing
,
Dan J. L.
Brett
,
Ivan P.
Parkin
,
Xuedan
Song
,
Liqiang
Mai
,
Guanjie
He
Diamond Proposal Number(s):
[32058, 33118]
Open Access
Abstract: Electrochemical urea splitting provides a sustainable and environmentally benign route for facilitating energy conversion. Nonetheless, the sustained efficiency of urea splitting is impeded by a scarcity of active sites during extended operational periods. Herein, an atomic heterostructure engineering strategy is proposed to promote the generation of active species via synthesizing unique Ru–O4 coordinated single atom catalysts anchored on Ni hydroxide (Ru1–Ni(OH)2), with ultralow Ru loading mass of 40.6 μg cm−2 on the nickel foam for commercial feasibility. Leveraging in situ spectroscopic characterizations, the structure-performance relationship in low and high urea concentrations was investigated and exhibited extensive universality. The boosted generation of dynamic Ni3+ active sites ensures outstanding activity and prominent long-term durability tests in various practical scenarios, including 100 h Zn–urea–air battery operation, 100 h alkaline urine electrolysis, and over 400 h stable hydrogen production in membrane electrode assembly (MEA) system under industrial-level current density.
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Nov 2023
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E01-JEM ARM 200CF
E02-JEM ARM 300CF
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Runjia
Lin
,
Liqun
Kang
,
Karolina
Lisowska
,
Weiying
He
,
Siyu
Zhao
,
Shusaku
Hayama
,
Dan
Brett
,
Graham
Hutchings
,
Furio
Corà
,
Ivan
Parkin
,
Guanjie
He
Diamond Proposal Number(s):
[29254, 29207]
Open Access
Abstract: Electrocatalytic oxygen reduction reaction (ORR) has been intensively studied for efficient and environmentally benign energy conversion processes. However, insufficient understanding of ORR 2e--pathway mechanism at the atomic level inhibits rational design of electrocatalysts with both high activity and selectivity, causing concerns including catalyst degradation due to Fenton reaction or poor efficiency of H2O2 electrosynthesis. Herein we show that the generally accepted ORR electrocatalyst design based on a Sabatier volcano plot argument optimises activity but is unable to account for the 2e--pathway selectivity; an extended “dynamic active site saturation” model that examines in addition the hydrogenation kinetics linked to the OOH* adsorption energy enables us to resolve the activity-selectivity compromise. Through electrochemical and operando spectroscopic studies on the ORR process governed by a series of Co-N x /carbon nanotube hybrids, a construction-driven approach that aims to create the maximum number of 2e- ORR sites by directing the secondary ORR electron transfer step towards the 2e- intermediate is proven to be attainable by manipulating O2 hydrogenation kinetics. Control experiments reveal the O2 hydrogenation chemistry is related to a catalyst reconstruction with lower symmetry around the Co active centre induced by the application of a cathodic potential. The optimised catalyst exhibits a ~100% H2O2 selectivity and an outstanding activity with an ORR potential of 0.82 V versus the reversible hydrogen electrode to reach the ring current density of 1 mA cm-2 by using rotating ring-disk electrode measurement, which is the best-performing 2e- ORR electrocatalyst reported to date, and approaches the thermodynamic limit.
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Mar 2023
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
E02-JEM ARM 300CF
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Longxiang
Liu
,
Liqun
Kang
,
Arunabhiram
Chutia
,
Jianrui
Feng
,
Martyna
Michalska
,
Pilar
Ferrer
,
David
Grinter
,
Georg
Held
,
Yeshu
Tan
,
Fangjia
Zhao
,
Fei
Guo
,
David
Hopkinson
,
Christopher
Allen
,
Yanbei
Hou
,
Junwen
Gu
,
Ioannis
Papakonstantinou
,
Paul
Shearing
,
Dan
Brett
,
Ivan P.
Parkin
,
Guanjie
He
Diamond Proposal Number(s):
[29340, 32501, 30614, 29809, 32058]
Open Access
Abstract: The electrochemical synthesis of hydrogen peroxide (H2O2) via a two-electron (2e-) oxygen reduction reaction (ORR) process provides a promising alternative to replace the energy-intensive anthraquinone process. However, the development of efficient electrocatalysts is still facing lots of challenges like insufficient understanding of active sites. Herein, we develop a facile template-protected strategy to synthesize a highly active quinone-rich porous carbon catalyst (PCC) for H2O2 electrochemical production. The optimized PCC900 exhibits unprecedented activity and selectivity, of which the onset potential reaches 0.83 V vs. reversible hydrogen electrode in 0.1 M KOH and the H2O2 selectivity is over 95 % in a wide potential range. Comprehensive synchrotron-based near-edge X-ray absorption fine structure (NEXAFS) spectroscopy combined with electrocatalytic characterizations reveals the positive correlation between quinone content and 2e- ORR performance. The effectiveness of chair-form quinone groups as the most efficient active sites is highlighted by the molecule-mimic strategy and theoretical analysis.
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Mar 2023
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