“…17 The main peaks at 23.1°, 29.4°, 36.1°, 39.4°, 43.1°, 47.5°, 48.5°, 56.5°, and 57.4°were assigned to (012), (104), ( 110), ( 113), ( 202), (018), ( 116), (122), and (214) reflections, respectively. In the previous study, 18 we found that the calcite-phased CaCO 3 (eggshell) was converted into CaO without the supply of H 2 into the reactor. The formation of Ca(OH) 2 following synthesis with 10 vol % H 2 in Ar was remarkable.…”