  A new multisensor (i.e. resistive and magnetic) $CrI_{3}$-$WTe_{2}$
heterostructure (HS) to detect the toxic gases $BrF_3$ and $COCl_2$ (Phosgene)
has been theoretically studied in our present investigation. The HS has
demonstrated sensitivity towards both the gases by varying its electronic and
magnetic properties when gas molecule interacts with the HS. Fast recovery time
($< 0.14 fs$) under UV radiation has been observed. We have considered two
configurations of $BrF_3$ adsorbed HS; 1) when F ion interacts with HS (C1) and
2) when Br ion interacts with HS (C2). In C1 case the adsorption energy
$E_{ad}$ is observed to be -0.66 eV while in C2 it is -0.95 eV. On the other
hand in case of $COCl_2$ $E_{ad}$ is found to be -0.42 eV. Magnetic moments of
atoms are also found to vary upon gas adsorption indicates the suitability of
the HS as a magnetic gas sensor. Our observations suggests the suitability of
$CrI_{3}$-$WTe_{2}$ HS to respond detection of the toxic gases like $BrF_3$ and
$COCl_2$.
