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Instruments / Technical Area	Publication Details	Published
B18-Core EXAFS E01-JEM ARM 200CF	General synthesis of single atom electrocatalysts via a facile condensation–carbonization process Weiming Chen , Xuanli Luo , Thomas J. A. Slater , Yongfang Zhou , Sanliang Ling , Rui Bao , Jesum Alves Fernandes , Jianshe Wang , Yi Shen Journal Of Materials Chemistry A 355 DOI: 10.1039/D0TA08115A Diamond Proposal Number(s): [23723, 17198] Show Abstract ▼ Abstract: The general and cost-effective synthesis of single atom electrocatalysts (SAECs) still remains a great challenge. Herein, we report a general synthetic protocol for the synthesis of SAECs via a simple condensation–carbonization process, in which furfural and cyanamide were condensation polymerized in the presence of polystyrene nanospheres and metal ions, followed by a pyrolysis to N-doped carbon nanosheet (NCNS) supported SAECs. Six types of SAECs containing platinum, palladium, gold, nickel, cobalt and iron were synthesized to demonstrate the generality of the synthesis protocol. This methodology affords a facile solution to the trade-off between support conductivity and metal loading of SAECs by optimizing the ratio of carbon/nitrogen precursors, i.e., furfural and cyanamide. The presence of single metal atoms was confirmed by high-angle annular dark field scanning transmission electron microscopy and X-ray absorption fine structure measurements. The three-dimensional distribution of single platinum atoms was vividly revealed by depth profile analysis using a scanning transmission electron microscope. The resulting SAECs showed excellent performance for glycerol electro-oxidation and water splitting in alkaline solutions. Notably, Pt/NCNSs possessed an unprecedent mass-normalized current density of 5.3 A per milligram of platinum, which is 32 times that of the commercial Pt/C catalyst. Density functional theory calculations were conducted to reveal the adsorption behavior of glycerol over the SAECs. Using Ni/NCNSs and Co/NCNSs as anodic and cathodic electrocatalysts, we constructed a solar panel powered electrolytic cell for overall water splitting, leading to an overall energy efficiency of 8.8%, which is among the largest solar-to-hydrogen conversion efficiencies reported in the literature.	Nov 2020
B18-Core EXAFS E01-JEM ARM 200CF	A versatile single-copper-atom electrocatalyst for biomass valorization Yongfang Zhou , Thomas J. A. Slater , Xuanli Luo , Yi Shen Applied Catalysis B: Environmental 324 DOI: 10.1016/j.apcatb.2022.122218 Diamond Proposal Number(s): [23723, 17198] Show Abstract ▼ Abstract: Single atom electrocatalysts (SAECs) exhibit intriguing catalytic performance due to their utmost atom-utilization efficiency and unique electronic structure. However, the application of SAECs is limited on simple reactions such as the hydrogen/oxygen evolution reactions, and oxygen/nitrogen reduction reactions. Herein, single copper atoms supported on nitrogen doped carbon nanosheets (Cu/NCNSs) were demonstrated as a versatile SAEC for biomass upgrade. The activity of Cu/NCNSs was benchmarked against commercial Cu nanoparticles. Twelve basic platform compounds including 5-hydroxymethylfurfural (HMF), furfural, glucose, formaldehyde, methanol, ethanol, isopropanol, ethylene glycol, glycerol, benzyl alcohol, formic acid, and oxalic acid were employed as substrates. The products of electro-oxidation of these substrates were analyzed by high performance liquid chromatography. The reaction pathways and mechanisms of substrate oxidation on Cu/NCNSs and Cu NPs were explored by in-situ electrochemical Raman spectra. HMF oxidation on Cu NPs followed the 5-diformylfuran (DFF) path at lower potentials, while it turned to 5-hydroxymethyl-2-furancarboxylic acid path at applied potentials over 1.67 V. For Cu/NCNSs, HMF oxidation followed the alcohol hydroxyl oxidation pathway, that is, the direction of generating DFF. The active sites for substrate oxidation on Cu/NCNSs are different from those on Cu NPs. This work broadened the application of SAECs in the field of biomass upgrade, and paved a new route to fabricate advanced electrocatalysts for biomass valorization.	Nov 2022
B18-Core EXAFS E01-JEM ARM 200CF	A high-throughput, solvent free method for dispersing metal atoms directly onto supports Emerson Cristofer Kohlrausch , Higor A. Centurion , Rhys Lodge , Xuanli Luo , Thomas Slater , Marcos J. L. Santos , Sanliang Ling , Valmor R. Mastelaro , Matthew J. Cliffe , Renato Vitalino Goncalves , Jesum Alves Fernandes Journal Of Materials Chemistry A DOI: 10.1039/D1TA08372D Diamond Proposal Number(s): [25120, 17198, 24914] Open Access Show Abstract ▼ Abstract: Atomically-dispersed metal catalysts (ADMCs) on surfaces have demonstrated high activity and selectivity in many catalytic reactions. However, dispersing and stabilising individual atoms in support materials in an atom/energy-efficient scalable way still presents a significant challenge. Currently, the synthesis of ADMCs involves many steps and further filtration procedures, creating a substantial hurdle to their production at industrial scale. In this work, we develop a new pathway for producing ADMCs in which Pt atoms are stabilised in the nitrogen-interstices of a graphitic carbon nitride (g-C3N4) framework using scalable, solvent-free, one-pot magnetron sputtering deposition. Our approach has the highest reported rate of ADMC production of 4.8 mg h-1 and generates no chemical waste. Deposition of only 0.5 weight percent of Pt onto g-C3N4 led to improved hydrogen production by factor of ca. 3333 ± 450 when compared to bare g-C3N4. PL analysis showed that the deposition of Pt atoms onto g-C3N4 suppressed the charge carrier recombination from the photogenerated electron-hole pairs of Pt/g-C3N4 thereby enhance hydrogen evolution. Scanning transmission electron microscope imaging before and after the hydrogen evolution reaction revealed that the Pt atoms stabilised in g-C3N4 have a high stability, with no agglomeration observed. Herein, it is shown that this scalable and clean approach can produce effective ADMCs with no further synthetic steps required, and that they can be readily used for catalytic reactions.	Nov 2021

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