For the same change in volume of fixed amount of perfect gas,  reversible work of expansion is maximum at 

$$\begin{gathered} \mathrm{W}=-2.303\mathrm{nRTlog}\frac{{\mathrm{V}}_{\mathrm{final}}}{{\mathrm{V}}_{\mathrm{initial}}}; \\ \mathrm{Change} \mathrm{in} \mathrm{volume} \mathrm{and} \mathrm{number} \mathrm{of} \mathrm{moles} \mathrm{of} \mathrm{gas} \mathrm{are} \mathrm{constant}; \\ \mathrm{Thus} {\mathrm{W}}_{\mathrm{rev}} \mathrm{is} \mathrm{maximum} \mathrm{at} \mathrm{higher} \mathrm{temperature}; \end{gathered}$$