\textbf{Doping Li and K into Na}$_{\mathrm{\mathbf{2}}}$\textbf{ZrO}$_{\mathrm{\mathbf{3}}}$\textbf{ Sorbent to Improve Its CO}$_{\mathrm{\mathbf{2}}}$\textbf{ Capture Capability}

Carbon dioxide is one of the major combustion products which once released into the air can contribute to global climate change. Solid sorbents have been reported in several previous studies to be promising candidates for CO$_{\mathrm{2}}$ sorbent applications due to their high CO$_{\mathrm{2}}$ absorption capacities at moderate working temperatures. However, at a given CO$_{\mathrm{2}}$ pressure, the turnover temperature (T$_{\mathrm{t}})$ of an individual solid capture CO$_{\mathrm{2}}$ reaction is fixed and may be outside the operating temperature range ($\Delta $T$_{\mathrm{o}})$ for a particularly capture technology. In order to shift such T$_{\mathrm{t}}$ for a solid into the range of $\Delta $T$_{\mathrm{o}}$, its corresponding thermodynamic property must be changed by changing its structure by reacting (mixing) with other materials or doping with other elements. As an example, by combining thermodynamic database searching with \textit{ab initio} thermodynamics calculations, in this work, we explored the Li- and K-doping effects on the T$_{\mathrm{t}}$ shifts of Na$_{\mathrm{2}}$ZrO$_{\mathrm{3}}$ at different doping levels. The obtained results showed that compared to pure Na$_{\mathrm{2}}$ZrO$_{\mathrm{3}}$, the Li- and K-doped mixtures Na$_{\mathrm{2-\alpha }}$M$_{\mathrm{\alpha }}$ZrO$_{\mathrm{3}}$ (M$=$Li, K) have lower T$_{\mathrm{t}}$ and higher CO$_{\mathrm{2}}$ capture capacities.