## 4 Reliable and Highly Sensitive Gas-Sensitive Materials for Intelligent Monitoring
### 2D (Two-Dimensional) Material Sensor Material
The band gap, adsorption energy, gas charge transfer, the closest atomic distance to the gas molecules, donor/acceptor characteristics of gas molecules, and band gap after adsorption of gas molecules have been compared in details, as shown in Table 3.  
Tellurium-two-dimensional elemental materials, due to their mild band gap, excellent environmental stability, and high room temperature carrier mobility, are widely attractive [99,100]. The excellent properties described above indicate that tellurium can be used in gas sensing directly [101,102]. [PERSON] et al. [93] studied the characteristics of decomposition products on monolayer tellurium based on density functional theory (DFT) calculations. The results are shown in Table 3, and the monolayer telluride has good adsorption and charge transfer capacity for the above components, especially SO2 and SOF2. Telluride is a 2D nanostructured material that can be synthesized in a variety of ways [103]. [PERSON] et al. [104] designed three types of tellurium-based gas sensors, including ohm-contact monolithic (RCTF), non-ohm-contact monolithic (DCTF), and thermally functioning droplet (HTF) sensors, to study the sensing performance by using the characteristics of tellurium with phosphorus-like fold structure, good air stability, and high gas \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Materials**} & \multirow{2}{*}{**E\({}_{\text{g}}\) (eV)**} & \multicolumn{2}{c}{**Gas Molecules**} & \multirow{2}{*}{**E\({}_{\text{ad}}\) (eV)**} & \multirow{2}{*}{**Qr (e)**} & \multirow{2}{*}{**d (Å)**} & \multirow{2}{*}{**Donor/Acceptor**} & \multirow{2}{*}{**E\({}_{\text{g}}\) (eV)**} & \multirow{2}{*}{**Refs.**} \\ \hline \multirow{6}{*}{Rh-BN monolayer} & \multirow{6}{*}{1.223} & H2S & \(-\)2.236 & 0.108 & - & acceptor & 2.352 & \\  & & SO2 & \(-\)2.328 & \(-\)0.294 & - & donor & 2.124 & \\  & & SOF2 & \(-\)3.411 & \(-\)0.509 & - & donor & 1.813 & \\  & & SO2F2 & \(-\)3.286 & \(-\)0.640 & - & Donor & 1.691 & \\ Ni-ZnO monolayer & \multirow{6}{*}{1.100} & SO2 & \(-\)2.38 & \(-\)0.183 & 1.89 & donor & 1.515 & \\  & & SOF2 & \(-\)2.19 & \(-\)0.148 & 1.95 & donor & 1.547 & \\  & & HF & \(-\)0.314 & \(-\)0.016 & 3.919 & donor & 1.214 & \\  & & SOF2 & \(-\)0.345 & \(-\)0.093 & 3.590 & donor & 1.231 & \\ Monolayer & \multirow{6}{*}{1.233} & SO2 & \(-\)0.382 & \(-\)0.158 & 3.278 & donor & 1.071 & \\ tellurium & & SO2F2 & \(-\)0.231 & \(-\)0.007 & 3.798 & donor & 1.219 & \\  & & H2S & \(-\)0.317 & 0.026 & 3.651 & acceptor & 1.225 & \\  & & SO2 & \(-\)2.58 & \(-\)0.446 & 2.086 & donor & 0.149 & \\ Ru-InN & \multirow{6}{*}{0.359} & SOF2 & \(-\)2.37 & \(-\)0.680 & 2.124 & donor & 0.121 & [94] \\ monolayer & & SO2F2 & \(-\)2.61 & \(-\)0.773 & 2.062 & donor & 0.139 & \\ Phosphorene & - & SO2 & \(-\)0.382 & \(-\)0.118 & 2.852 & donor & - & [95] \\  & & H2S & \(-\)0.208 & \(-\)0.047 & 2.366 & donor & - & [95] \\  & & SO2 & \(-\)1.54 & \(-\)0.28 & 2.30 & donor & 1.071 & \\ InP3 monolayer & \multirow{6}{*}{1.018} & SOF2 & \(-\)0.77 & \(-\)0.12 & 2.73 & donor & 0.983 & [96] \\  & & SO2F2 & \(-\)0.31 & \(-\)0.05 & 3.51 & acceptor & 1.017 & \\  & & H2S & \(-\)0.269 & \(-\)0.013 & 3.608 & donor & 1.42 & \\  & & SO2 & \(-\)0.541 & \(-\)0.232 & 2.974 & donor & 1.76 & \\ monolayer SbP & \multirow{6}{*}{0.28} & HF & \(-\)0.315 & \(-\)0.160 & 2.214 & donor & 1.42 & [97] \\  & & SOF2 & \(-\)0.286 & \(-\)0.04 & 3.506 & donor & 2.05 & \\  & & SO2F2 & \(-\)0.255 & 0.02 & 3.554 & acceptor & 2.05 & \\  & & H2S & \(-\)0.464 & 0.028 & - & acceptor & - & \\ Stone-Wales (SW) defective Sb & - & SOF2 & \(-\)0.731 & 0.258 & - & acceptor & - & \\  & & SOF2 & \(-\)0.528 & 0.080 & - & acceptor & - & \\  & & SO2F2 & \(-\)0.400 & 0.071 & - & acceptor & - & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Band gap, adsorption energy, gas charge transfer, the closest atomic distance to the gas molecules, donor/acceptor characteristics of gas molecules, and band gap after adsorption of gas molecules. sensitivity.