Further insights into catalytic pyrolysis of industrial lignin over lanthanum ferrite perovskite

[Display omitted] •As-fabricated LaFeO3 catalyst owns both acid-base sites and oxygen vacancies.•LaFeO3 catalyst exhibits excellent activity and recyclability as well as anti-coking.•Use of LaFeO3 catalyst promotes the breakage of aryl ether bonds and aromatization.•Lewis acid-base sites and oxygen vacancies jointly govern the catalytic progress.•Catalytic microwave pyrolysis mainly occurs in the microporous channels of LaFeO3. It is essential for accelerating the development and deployment of advanced lignocellulosic biorefineries to utilize industrial lignin availably. Herein, rare earth lanthanum ferrite (LaFeO3) perovskite fabricated via co-precipitation method employed as a catalyst in an ex-situ mode for the microwave-assisted pyrolysis of softwood kraft pulp lignin (SKPL), aiming to evaluate its applicability and delve deeply into understanding the underlying mechanisms that govern the catalytic action during the pyrolysis process. The results showed that LaFeO3 catalyst exhibited outstanding activity for affording monophenols with a selectivity of 83.71%, and the product selectivity remained above 94% after six consecutive cycles. Mechanism studies declared that the catalytic pyrolysis was initiated by the electrons loss of Fe2+ species in LaFeO3 catalyst, and the subsequent active oxygen vacancies (after obtaining the electrons) contributed to adsorbing oxygen-containing motifs in SKPL, thus promoting the breakage of C-O bonds and aromatization reactions. Concurrently, the augmentation in Fe3+ species facilitated the cleavage of β-O-4 aryl ether bonds and β–β linkages (pinoresinol structures), thereby contributing to the generation of monophenols. In essence, LaFeO3 perovskite emerged as an adept catalyst for the ex-situ microwave-assisted pyrolysis of SKPL, enabling the production of high value-added monophenols.