Hydrothermal Synthesis of La<sub>2</sub>O<sub>2</sub>CO<sub>3</sub> and La<sub>2</sub>O<sub>3</sub> Catalysts: Influence of Alkaline Solution on Low-Temperature OCM Performance
TOPICS IN CATALYSIS, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Publication Date: 2026
- Doi Number: 10.1007/s11244-026-02288-z
- Journal Name: TOPICS IN CATALYSIS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Biological Science Database (ProQuest), Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Open Archive Collection: AVESIS Open Access Collection
- Istanbul University Affiliated: No
Abstract
The oxidative coupling of methane (OCM) offers a direct route to produce value-added C2 hydrocarbons; however, achieving high activity and selectivity at low temperatures remains challenging. In this experimental study, La2O2CO3 and La2O3 nanowire catalysts were synthesized hydrothermally using different alkaline precipitants under identical conditions. Structural and surface analyses (XRD, FE-SEM, BET) demonstrate the decisive role of the precipitant in controlling phase composition, morphology, and surface area. The ammonia-derived La2O2CO3 catalyst (A-500) demonstrated stable OCM activity at temperatures as high as 350 degrees C, yielding a C2+ yield of 12.3%. This finding indicates that the reported onset temperature for OCM is among the lowest documented to date. As the temperature increased, the A-500 demonstrated a maximum C2+ yield of 13.1% at 500 degrees C, exhibiting suppressed COx formation. Over the duration of 50 h, the system maintained approximately 31% CH4 conversion and 44% C2+ selectivity without any discernible deactivation. The results suggest that OCM performance is governed by a coupled structural parameter space in which crystallite size, morphology, and surface area act synergistically to determine catalytic efficiency. Consequently, the integration of hydrothermal synthesis with a judicious selection of precipitant agents has yielded La-based catalysts that exhibit remarkably low-temperature activity and prolonged durability. This approach provides a set of pragmatic design principles for the development of catalysts in the context of low-temperature OCM.