Determination of thermodynamic parameters of nanocalcium molybdate reaction system by microcalorimetry

Calcium molybdate (CaMoO₄) nanorods with uniform size were harvested by a gentle and facile reverse-microemulsion method. Each of the prepared nanorods was about 250 nm in length and 80 nm in diameter. By combining thermodynamic and thermokinetic theories, thermodynamic parameters of the nanoCaMoO₄ reaction system such as standard molar enthalpy of reaction (Δ_rH_m^θ), standard molar activation Gibbs free energy of reaction (Δ_r^≠G_m^θ), standard molar activation enthalpy of reaction (Δ_r^≠H_m^θ) and standard molar activation entropy of reaction (Δ_r^≠S_m^θ) were successfully acquired by applying microcalorimetry. The significant differences of the thermodynamic parameters between nanoCaMoO₄ and bulk CaMoO₄ reaction systems are also discussed and the reason can be rooted in the surface effect of nanomaterials.