A novel family of mixed gallium aluminum phosphorus oxynitrides: their synthesis, characterization and utilization in heterogeneous catalysis

Structural Investigation of Mixed Nitrided Galloaluminophosphates “AlGaPON” by EELS, XAS, and XPS Spectroscopies

“…Indeed, it has been shown that the Al/Ga and (Al#Ga)/P ratios were maintained during nitridation at this temperature and that the weightloss recorded during nitridation corresponded to the replacement of three oxygen atoms by two nitrogen atoms (13). Besides, we veri"ed that the O/N atomic ratio calculated for the AG9N5 sample (O/N "1.2) was similar to the atomic ratio established from the chemical dosage of the O and N total content of the samples (O/N "1.1) (LECO elemental analyzer equipped with a TC-346 program and an EF-400 oven).…”

“…The high surface area, amorphous Al Ga PO precursor was synthesized by a process developed by Kearby (31) for aluminophosphates and adapted for the &&(Al, Ga)PO'' compositions (13). A solution of adequate amounts of Ga>, Al>, and H PO (2M) (P/(Ga#Al) and Ga/Al atomic ratios of 1) was cooled at 03C in a dry ice}alcohol bath.…”

“…The choice of experimental conditions for nitridation is conditioned by the Al/Ga ratio of the precursor (13). In all cases, however, the nitridation temperature cannot exceed 8003C; indeed at higher temperatures, a partial reduction of P> phosphorus atoms by ammonia with formation of volatile phosphines leads to phosphorus-de"cient oxynitrides with the general formula Al Ga…”

“…The mixed galloaluminophosphates obtained by the Kearby (31) method are highly divided X-ray amorphous white powders (13). Nitrogen adsorption and desorption isotherms recorded on those samples at !1963C present a hysteresis loop, characteristic of type IV isotherms, which indicates the prevalence of mesopores (44).…”

“…More recently, we developed a new family of mixed nitrided galloaluminophosphates &&AlGaPON''. Those solids are synthesized by ammonolysis of an amorphous Al Ga PO precursor (13). This precursor has a marked acid character due to the presense of surface BroK nsted and Lewis acid sites.…”