Pitfalls and reproducibility of in situ synchrotron powder X‐ray diffraction studies of solvothermal nanoparticle formation. Issue 2 (30th March 2018)

• Record Type: Journal Article
• Authors: Andersen, Henrik L.; Bøjesen, Espen D.; Birgisson, Steinar; Christensen, Mogens; Iversen, Bo B.
• Is Part Of: Journal of applied crystallography. Volume 51:Issue 2(2018)
• Page Start: 526
• Page End: 540
• Publication Date: 2018-03-30
• Subjects: in situ powder X‐ray diffraction -- solvothermal synthesis -- nanoparticles -- Rietveld refinement -- reproducibility; Crystallography -- Periodicals; 548.05
• DOI: 10.1107/S1600576718003552
• Languages: English
• ISSNs: 0021-8898

Abstract

Abstract : This article presents a compilation of useful advice for conducting in situ powder X‐ray diffraction studies of solvothermal nanoparticle formation along with a meticulous experimental evaluation of the effective errors, reproducibility and dependability of the extracted time‐resolved parameters. Abstract : In situ powder X‐ray diffraction (PXRD) is a powerful characterization tool owing to its ability to provide time‐resolved information about phase composition, crystal structure and microstructure. The application of high‐flux synchrotron X‐ray beams and the development of custom‐built reactors have facilitated second‐scale time‐resolved studies of nanocrystallite formation and growth during solvothermal synthesis. The short exposure times required for good time resolution limit the data quality, while the employed high‐temperature–high‐pressure reactors further complicate data acquisition and treatment. Based on experience gathered during ten years of conducting in situ studies of solvothermal reactions at a number of different synchrotrons, a compilation of useful advice for conducting in situ PXRD experiments and data treatment is presented here. In addition, the reproducibility of the employed portable in situ PXRD setup, experimental procedure and data analysis is evaluated. This evaluation is based on repeated measurements of an LaB6 line‐profile standard throughout 5 d of beamtime and on the repetition of ten identical in situ synchrotron PXRD experiments on the hydrothermal formation of γ‐Fe2 O3 nanocrystallites. The study reveals inconsistencies in the absolute structural and microstructural values extracted by Rietveld refinement and whole powder pattern modelling of the in situ PXRD data, but also illustrates the robustness of trends and relative changes in the extracted parameters. From the data, estimates of the effective errors and reproducibility of in situ PXRD studies of solvothermal nanocrystallite formation are provided.