Efficient Strategy to Regenerate Phosphorus-Poisoned Cu-SSZ-13 Catalysts for the NH₃-SCR of NO_x: The Deactivation and Promotion Mechanism of Phosphorus

Abstract

Despite the successful commercialization of Cu-SSZ-13 catalysts as efficient ammonia-selective catalytic reduction (NH3-SCR) catalysts in diesel vehicles for NO x elimination, their sensitivity toward phosphorus poisoning is one of the primary challenges to practical applications. In this study, an efficient method was used to regenerate a phosphorus-poisoned Cu-SSZ-13 catalyst by washing with hot water. The mechanism of deactivation and regeneration of the Cu-SSZ-13 catalyst was deeply investigated by a series of careful characterizations of fresh, poisoned, and regenerated catalysts. After regeneration, the recovery of the decreased accessibility and porosity, deactivated Brønsted acid sites, and Cu2+ ions resulted in the restoration of the decreased activity and hydrothermal stability of the poisoned Cu-SSZ-13. At a low phosphorus loading (0.2 mmol/gcatal, 0.54 wt %), the promotion effect of phosphorus on the SCR performance was observed after regeneration, which was attributed to the decrease in the content of CuO species and recovery of the acid sites and active Cu2+ ions after regeneration. Additionally, the combination of washing with hot water and hydrothermal aging results in good recovery of the SCR performance of the phosphorus-poisoned catalyst. This work focuses on the regeneration of a phosphorus-poisoned Cu-SSZ-13 catalyst, which provides an efficient method to prolong the lifespan of the Cu-SSZ-13 catalyst in practical applications.

Ultralow-Temperature NOx Reduction over SmMn2O5 Mullite Catalysts Via Modulating the Superficial Dual-Functional Active Sites

“…have been developed as NH 3 -SCR catalysts for reduction of NO x from nonelectric industries. Nevertheless, their performance can hardly meet the practical demand in the ultralow-temperature deNO x situation. − …”

Low-Cost CuX Catalyst from Blast Furnace Slag Waste for Low-Temperature NH3-SCR: Nature of Cu Active Sites and Influence of SO2/H2O

“…The Cu 2p, O 1s, Si 2p, and Al 2p spectra were observed on the four catalysts, and the S 2p and Cl 2p appeared on Cu­(S)­X and Cu­(C)­X catalysts, while there was no peak that belonged to N 1s on the Cu­(N)­X catalyst. From Cu 2p (Figure a), there were three broad peaks at 953, 945, and 933 eV, belonging to Cu 2p 1/2 , shake-up satellite peak, and Cu 2p 3/2 , respectively. ,− After the peak-fitting deconvolution using Avantage software, the Cu 2p 3/2 spectrum was fitted into two characteristic peaks assigned to isolated Cu 2+ species (934 eV) and Cu + species (932.6 eV), respectively. ,, It could be noted that the Cu­(N)­X catalyst had more concentration of isolated Cu 2+ species, and the ratio of isolated Cu 2+ was the highest among the Cu­(S)­X, Cu­(N)­X, Cu­(C)­X, and Cu­(N)­X–S catalysts (Table S3). From previous studies, , the higher concentration of isolated Cu 2+ species could provide more active sites for the reaction, thereby the Cu­(N)­X catalyst had higher SCR activity than other catalysts.…”

“…Several peaks were discovered around g = 2.38, 2.22, and 2.08 in Figure 4d. According to the literature, 9,42,43 the peak at g = 2.38 could be attributed to the active Cu 2+ species, the peak at g = 2.22 was assigned to the hyperfine structure of the 27 Al frame, and the peak at g = 2.08 belonged to the surface O 2− anions. It could be found that the Cu(N)X catalyst had the highest amount of active Cu 2+ species, while the Cu(C)X catalyst had the lowest amount, which was consistent with XPS result in Table S3, resulting in one of the reasons for the higher SCR activity of the Cu(N)X catalyst and the lower SCR activity of the Cu(C)X catalyst, which was also consistent with the catalytic activity results.…”

“…Recently, zeolite-based catalysts have been extensively studied for application in NH 3 -SCR reaction conditions, among which Cu-zeolites have drawn much attention. − Tarach et al investigated the catalytic activity of Cu-exchanged zeolites with different frameworks, and the results found that the Cu-ZSM-5 catalyst displayed the best NH 3 -SCR activity. Beale et al investigated that the Cu-SSZ-13 catalyst had extraordinary de-NO x activity and obtained NH 3 -SCR performance was related to the migration behavior of Cu ions.…”

Review of the application of Cu-containing SSZ-13 in NH3-SCR-DeNOx and NH3-SCO

“…96,155 To regenerate the P-poisoned Cu-SSZ-13 catalysts, phosphorous species in the catalysts should be removed. As an example of that approach, Chen et al 71 successfully applied the combination of washing with hot water (90 °C) and hydrothermal treatment (800 °C for 12 h) to recover the activity of the phosphorous-poisoned Cu-SSZ-13.…”