Remarks on critical metrics of the scalar curvature and volume functionals on compact manifolds with boundary

We provide a general B\"ochner type formula which enables us to prove some rigidity results for V-static spaces. In particular, we show that an n-dimensional positive static triple with connected boundary and positive scalar curvature must be isometric to the standard hemisphere, provided that the metric has zero radial Weyl curvature and satisfies a suitable pinching condition. Moreover, we classify V-static spaces with non-negative sectional curvature.