## 4 Conclusions  
Keeping in mind the sustainable growth of human life, contaminant-free approaches are of crucial necessity. Although substantial efforts have been employed to construct variant types of photocatalysts, minimal research data have been reported to solve these problems comprehensively, among which g-C\({}_{3}\)N\({}_{4}\)/CQDs-based photosystems have been studied and explored extensively. Due to modified electronic structure, CQDs-decorated g-C\({}_{3}\)N\({}_{4}\) photosystems have become fast growing field of research. This article initially provides the designing strategies and physicochemical properties of g-C\({}_{3}\)N\({}_{4}\)/CQDs-based \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type of Composite** & **Target Pollutant** & **Source of Illumination Light** & **Degradation Efficiency** & **Ref.** \\ \hline Carbon quantum dots/g-C\({}_{3}\)N\({}_{4}\) & Dclofenac (DCF) & 300 W Xe lamp (\(\lambda>\) 420 nm) & Dclofenac degradation: 100\% within & [68] \\ \hline g-C\({}_{3}\)N\({}_{4}\)/Carbon-dots nanosheet & Sulfadiazine (SDZ) & 500 W Xe lamp (\(\lambda<\) 420 nm) & SDZ degradation: 97.82\% within & [34] \\ \hline Carbon-dots/g-C\({}_{3}\)N\({}_{4}\) & SDZ & Visible-light & SDZ degradation: 92.8\% within & [69] \\ \hline Carbon quantum dots/g-C\({}_{3}\)N\({}_{4}\) & Carbamazepine (CBZ) & UV-light with cutoff filter & CBZ degraded with first-order rate & [70] \\ \hline High-crystalline & Tetracycline (TC) & 300 W Xe lamp (\(\lambda>\) 420 nm) & TC degradation: 86\% within 120 min & [71] \\ \hline Acidified g-C\({}_{3}\)N\({}_{4}\)/Carbon & Ibuprofen (IBU) & 300 W Xe lamp (\(\lambda>\) 420 nm) & IBU degradation: 91.0\% within & [72] \\ quantum dots-3 wt\%/CdIn\({}_{3}\)S\({}_{4}\) & Chloramphenicol (CMP) & 300 W Xe lamp with cutoff filters (380–780 nm) & CMP degradation: 99.1\% within 1 h & [73] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: \(Cont.\)nanocomposites. The review mainly summarized the g-C\({}_{3}\)N\({}_{4}\)/CQDs-based nanocomposites in the field of environmental remediation, including the degradation of dyes and different antibiotics, and CO\({}_{2}\) conversion into valuable chemicals. The g-C\({}_{3}\)N\({}_{4}\)/CQDs-based photocatalysts were mainly explored for dye and antibiotic degradation, as per existing literature reports, indicating their effectiveness in the wastewater remediations. Still, the formation of harmful secondary by-products during photodegradation processes needs major consideration to avoid such pollutant products. The development of effective methods to load CQDs on g-C\({}_{3}\)N\({}_{4}\)-based nanocomposites and to enhance the recyclability of g-C\({}_{3}\)N\({}_{4}\)/CQDs heterostructure are also crucial parameters. This g-C\({}_{3}\)N\({}_{4}\)-based heterostructural could enhance the light-harvesting capability, charge kinetic reactions, and their separation efficiency, ultra-high surface area, and photochemical stability, giving promoted photoactivity of the photocatalyst. However, despite the aforementioned advantages and achievements in the wastewater treatment, there still exists some ongoing challenges and problems that hampers the practical applications of the g-C\({}_{3}\)N\({}_{4}\)/CQDs-based nanocomposite:  
1. Even though there is prodigious development in the modified g-C\({}_{3}\)N\({}_{4}\)-based composite, the visible-light utilization is still limited to near blue-violet spectrum range, and subsequently, the efficacy of light-harvesting and solar-light employment is not high. However, the g-C\({}_{3}\)N\({}_{4}\)/CQDs nanocomposites are only limited to laboratory scale due to photocatalyst dissolution during photoreaction and corrosion of the photocatalyst. Hence, future research should focus more on developing modified g-C\({}_{3}\)N\({}_{4}\) by constructing more stable structural framework and stronger bonds between the components.