Photothermal Nanoconfinement Reactor: Boosting Chemical Reactivity with Locally High Temperature in a Confined Space

Abstract

A photothermal nanoconfinement reactor (PNCR) system is proposed and demonstrated by using hollow carbon nanospheres (HCNs) to enhance the performance of the chemical reaction. Under light irradiation, the local temperature of the HCN inner void space was much higher than the bulk solution temperature because the confined space concentrates heat and inhibits heat loss. Using the temperature‐sensitive model reaction, peroxydisulfate (PDS) activation to oxidize micropollutant, it is shown that the degradation rate of sulfamethoxazole in the PNCR system is 7.1 times of that without nanoconfinement. It is further discovered that the high‐quality local heat inside the nanoconfined space shifted the model reaction from an otherwise non‐radical pathway to a radical‐based pathway. This work provides an interesting strategy to produce a locally high temperature, which has a wide range of applications to energy and environmental fields.

Plasma Ag-Modified α-Fe2O3/g-C3N4 Self-Assembled S-Scheme Heterojunctions with Enhanced Photothermal-Photocatalytic-Fenton Performances

“…In addition, Ag/α-Fe 2 O 3 /g-C 3 N 4 also showed the best performance in the degradation experiments of TC with a 93.6% degradation rate in 150 min ( Figure 6 c), and approximately maintained this degradation rate for all five cycles ( Figure 6 d). The first-order reaction kinetic curves show that apparent reaction rate of Ag/α-Fe 2 O 3 /g-C 3 N 4 was 2.6 times that of pure g-C 3 N 4 ( Figure 6 e), and Ag/α-Fe 2 O 3 /g-C 3 N 4 has relatively excellent TC degradation compared to other recently reported photocatalysts of the same type ( Table S2 ), which was the combined effect of S-Scheme heterojunction and photothermal effect to enhance the chemical reaction rate [ 19 , 56 ]. The radical quenching experiments showed that ·OH played a dominant role in the degradation of TC, followed by vacancies, and the superoxide radical ( ) at last ( Figure 6 f) [ 58 ].…”

“…The temperature of g-C 3 N 4 solution system under light increased from the initial 19.4 °C to 32.3 °C with a temperature increase of 12.9 °C, while the temperature of the ternary heterojunction increased from the initial 19.7 °C to 59.1 °C at the same condition, which was three times higher than that of pure g-C 3 N 4 , indicating that Ag/α-Fe 2 O 3 /g- C 3 N 4 offers a more significant photothermal effect. Ag/α-Fe 2 O 3 /g-C 3 N 4 ternary photocatalysts can convert part of the absorbed photon energy into thermal energy through the photothermal effect to form a local thermal environment near the catalyst surface in a photocatalytic process, thus increasing the near-field chemical reaction rate of the catalyst and enhancing the photocatalytic performance of the catalyst [ 13 , 56 , 57 ].…”