# Application of Quantum Dots for Photocatalytic Hydrogen Evolution Reaction
## 2 Quantum Dots-Based Photocatalyst for Hydrogen Evolution
In a majority of cases, semiconductor QDs serve as light absorbers to capture solar light during photocatalytic reactions. Moreover, owing to the small size of QDs, they exhibit not only a short electron-hole diffusion distance that facilitates the efficient separation of electron-hole \begin{table}
\begin{tabular}{l l l l l l l} \hline \hline
**Photocatalyst** & **Cocatalyst** & **Reaction** & **Light** & **H\({}_{2}\) Generation** & **Referenced** & **QDs** \\  & & **Medium** & **Source** & **(mmol h\({}^{-1}\)g\({}^{-1}\))** & **Sample/Enhancement** & **Ref.** & **Size** \\ \hline Ni\({}_{2}\)P QDs/g-C\({}_{3}\)N\({}_{4}\) & Ni\({}_{2}\)P QDs & TEOA & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\geq\) 420 nm) \\ \end{tabular} & 1.51 & pure g-C\({}_{3}\)N\({}_{4}\)/11 & [52] & 4-5 \\ \hline g-C\({}_{3}\)N\({}_{4}\)@Ti\({}_{3}\)C\({}_{2}\) & Ti\({}_{3}\)C\({}_{2}\) QDs & TEOA & \begin{tabular}{l} 300 W Xe lamp \\ with a 1.5 AM filter \\ \end{tabular} & 5.12 & g-C\({}_{3}\)N\({}_{4}\)/26 & [53] & \\ \hline Au QDs/rimous & Au QDs & Na\({}_{2}\)S and Na\({}_{2}\)SO\({}_{3}\) & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\geq\) 420 nm) \\ \end{tabular} & 0.60 & CdS nanospheres/1.8 & [54] & 3.5 \\ \hline Ag QDs/g\({}_{2}\)C\({}_{3}\)N\({}_{4}\) & Ag QDs & 20 vol\% methanol & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\geq\) 420 nm) \\ \end{tabular} & 0.0181 & g-C\({}_{3}\)N\({}_{4}\)/4.6 & [55] & \\ \hline CDs/g-C\({}_{3}\)N\({}_{4}\) & CDs & TEOA & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\geq\) 420 nm) \\ \end{tabular} & 2.34 & g-C\({}_{3}\)N\({}_{4}\)/4.6 & [56] & 4 \\ \hline CQDs/g-C\({}_{3}\)N\({}_{4}\) & CQD & Methanol & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\geq\) 420 nm) \\ \end{tabular} & 3.54 & g-C\({}_{3}\)N\({}_{4}\) nanotubes/2.5 & [28] & \\ \hline CQDs/TiO\({}_{2}\) & CQDs & Methanol & \begin{tabular}{l} 500 W halogen lamp \\ (\(\lambda\geq\) 450 nm) \\ \end{tabular} & 0.0085 & TiO\({}_{2}\)/4 & [30] & 4-6 \\ \hline P-TCN\({}^{\circ}\)/GQDs & GQDs & 20 vol\% methanol & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\geq\) 420 nm) \\ \end{tabular} & 1.12 & bulk carbon nitride/9 & [57] & \\ \hline Ag/CODs/g-C\({}_{3}\)N\({}_{4}\) & Ag/CQDs & TEOA & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\) = 400 nm) \\ \end{tabular} & 0.627 & g-C\({}_{3}\)N\({}_{4}\)/6.7 & [58] & 2.59 \\ \hline Pt QDs/BiOBr & Pt QDs & Na\({}_{2}\)S and Na\({}_{2}\)SO\({}_{3}\) & 300 W Xe lamp & 0.0320 & BiOBr/143 & [59] & \\ \hline Ni QDs/CdS & Ni QDs & Lactic acid & \begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\) = 420 nm) \\ \end{tabular} & 10.3 & CdS/30 & [60] & 5.1 \\ \hline CdS QDs/NiO-66 & & Na\({}_{2}\)S and Na\({}_{2}\)SO\({}_{3}\) & \begin{tabular}{l} 225 W Xe light \\ (\(\lambda\) = 420 nm) \\ \end{tabular} & 15.32 & \begin{tabular}{l} UiO-66- \\ (SH)2/CdS/25.3 \\ \end{tabular} & [61] & 1 \\ \hline MoS\({}_{2}\) QDs/Cs\({}_{3}\)Bi\({}_{2}\)I\({}_{9}\) & MoS\({}_{2}\) QDs & Ethanol, HI/H\({}_{2}\)PO\({}_{2}\) mixed & \
\begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\) = 420 nm) \\ \end{tabular} & 6.09 & Cs\({}_{3}\)Bi\({}_{2}\)I\({}_{9}\)/9.8 & [62] & 2-5 \\ \hline N-GQDs/PUCN d & N-GQDs & TEOA &
\begin{tabular}{l} 300 W Xe lamp \\ (\(\lambda\geq\) 400 nm) \\ \end{tabular} & 0.529 & PUCN/208 & [63] & \\ \hline \hline \end{tabular}  
* Compared with the reference sample, the enhancement factor of the photocatalytic performance. b AQY: apparent quantum yield. c P-TCN: phosphorus-doped hexagonal tubular carbon nitride. d 0 D nitrogen-doped graphene quantum dots (N-GQDs) on 2D porous ultrathin carbon nitride (PUCN).  
\end{table} 
Table 1: _Cont._pairs and weakens the adverse effect of interior recombination centers, but they also show also abundant surface sites that accelerate H\({}_{2}\) production.