Synthesis of a chabazite-supported copper catalyst with full mesopores for selective catalytic reduction of nitrogen oxides at low temperature

Abstract

A series of meso-microporous copper-supporting chabazite molecular sieve (Cu-SAPO-34) catalysts with excellent performance in low-temperature ammonia selective catalytic reduction (NH3-SCR) have been synthesized via a one-pot hydrothermal crystallization method. The physicochemical properties of the catalysts were characterized by scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption measurements, X-ray diffraction, 27Al magic angle spinning nuclear magnetic resonance, diffuse reflectance ultraviolet-visible spectroscopy, inductively coupled plasma-atomic emission spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction measurements, and electron paramagnetic resonance analysis. The formation of micro-mesopores in the Cu-SAPO-34 catalysts decreases diffusion resistance and greatly improves the accessibility of reactants to catalytic active sites. The main active sites for NH3-SCR reaction are the isolated Cu2+ species displaced into the ellipsoidal cavity of the Cu-SAPO-34 catalysts.