fig2
From: Rational engineering of hydroxyapatites for sustainable chemicals, H2, biofuels and CO2 conversion
Figure 2. (A) HAP hexagonal crystal structure unit cell with two Ca sites, Ca(I) and Ca(II) sites. Reproduced from Ref.[18] under CC BY 4.0 license. (B) Product selectivity at 50% ethanol conversion: (▲) total Guerbet alcohols, (●) 1,3-butadiene (■), ethylene. Reproduced from Ref.[19] with permission from Elsevier. (C) Moles of Ca2+ released to the solution as a function of moles of Pb2+. Reproduced from Ref.[20] with permission from Elsevier. (D) 43Ca MAS spectra of PbxCa10-x(VO4)(PO4)5(OH)2 (x = 0, 2, 4). Reproduced from Ref.[21] with permission from American Chemical Society.
