Diamond Annual Review 2023/24

30 D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 2 3 / 2 4 Structures and Surfaces Group Science Highlights Double the fun: Diamond’s versatile soft X-ray (VERSOX) beamline adds a second branch and operando cells Users bring a wide range of samples to Diamond’s Versatile Soft X-ray (VERSOX) beamline, including heterogeneous catalysts, pharmaceuticals and biomaterials for study under realistic conditions, liquids and ices for environmental and space science studies, heritage artefacts, electronic and photonic materials. The common factor in these experiments is a desire to explore the chemical nature and composition of the near-surface regions of the samples, using soft X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. Soft X-ray and X-ray absorption spectroscopy (XAS), also called near- edge X-ray absorption fine-structure (NEXAFS) spectroscopy and X-ray photoelectron Spectroscopy (XPS), allow researchers to collect elemental, chemical and structural information about solids, liquids and gases. These techniques are also ideal for probing the interfaces between these phases ( j solid-gas, solid-liquid, liquid-vapour) and local interactions at the surfaces and in sub-surfaces of materials. Diamond’s VERSOX beamline (B07) now comprises two separate branches, with a total of three end-stations, allowing studies of a wide range of interfaces and materials. Experiments can be conducted at ambient pressure, or in an extended pressure range from 1 x 10 - 10 mbar to 1 x 103 mbar. The beamline and end-stations use advanced software controls to maximises sample throughput and ease-of-use. BO7-C second end-station provides specialised sample environments, including a low-cost, reliable microreactor for heterogeneous catalysis and an operando electrochemical cell. For operando / in-situ near ambient pressure (NAP) soft X-ray XPS and NEXAFS studies, suitable reaction cells enable users to track the chemical state and structural properties of catalytically active materials under realistic reaction conditions. At B07 beamline, an electrochemical flow cell was developed in collaboration with Redox.me for operando X-ray spectroscopy of liquids and electro(photo)catalysts.It allows the researchers to probe a wide range of electrochemical systems, including water and CO 2 electrolysers, fuel cells, batteries, and electrosynthesis of fine chemicals. For instance, electrolysis of water, producing hydrogen by splitting water. With the current focus on replacing fossil fuels with more sustainable energy sources, one of the potential options is called green hydrogen, and that’s hydrogen produced using renewable electricity. At the moment, that’s not an affordable option, and one of the challenges is the durability of the catalyst used during the reaction. This new cell allows the researchers to look at these fundamental challenges and probe the structure and the interface of the catalyst and the electrolyte in the cell in real-time during reaction. This new research capability opens up exciting opportunities for the B07 beamline user community, both academic and industrial. Grinter, D.C. et al . DOI:10.1107/S1600577524001346 Kumar, S. et al . DOI:10.1088/2515-7655/ad54ee Figure: Schematic illustration of the electro(photo)chemical flow cell operation for operando measurements in ES2 of the B07 B beamline.