  Charge transfer between molecules and catalysts plays a critical role in
determining the efficiency and yield of photo-chemical catalytic processes. In
this paper, we study light-induced electron transfer between transition metal
doped aluminium clusters and CO$_2$ molecules using first-principles
time-dependent density-functional theory. Specifically, we carry out
calculations for a range of dopants (Zr, Mn, Fe, Ru, Co, Ni and Cu) and find
that the resulting systems fall into two categories: Cu- and Fe-doped clusters
exhibit no ground state charge transfer, weak CO$_2$ adsorption and
light-induced electron transfer into the CO$_2$. In all other systems, we
observe ground state electron transfer into the CO$_2$ resulting in strong
adsorption and predominantly light-induced electron back-transfer from the
CO$_2$ into the cluster. These findings pave the way towards a rational design
of atomically precise aluminium photo-catalysts.
