Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

CeO2-, ZrO2-, and La2O3-supported Rh-Pt catalysts were tested to assess their ability to catalyze the steam reforming of ethanol (SRE) for H2 production. SRE activity tests were performed using EtOH:H2O:N2 (molar ratio 1:3:51) at a gaseous space velocity of 70,600 h−1 between 400 and 700 °C at atmospheric pressure. The SRE stability of the catalysts was tested at 700 °C for 27 h time on stream under the same conditions. RhPt/CeO2, which showed the best performance in the stability test, also produced the highest H2 yield above 600 °C, followed by RhPt/La2O3 and RhPt/ZrO2. The fresh and aged catalysts were characterized by TEM, XPS, and TGA. The higher H2 selectivity of RhPt/CeO2 was ascribed to the formation of small (~5 nm) and stable particles probably consistent of Rh-Pt alloys with a Pt surface enrichment. Both metals were oxidized and acted as an almost constant active phase during the stability test owing to strong metal-support interactions, as well as the superior oxygen mobility of the support. The TGA results confirmed the absence of carbonaceous residues in all the aged catalysts.

Antonio Maura y el papel del II Reich en las negociaciones hispano-francesas sobre Marruecos de 1903-1904

En la primera parte del artículo se aborda el problema que ha de afrontar el estadista Antonio Maura al convertirse en el jefe del gobierno español, a finales de 1903 y consistente en concluir el proceso de negociación sobre Marruecos entablado con Francia desde 1901. Se resalta el carácter continuista del ideario colonial de Maura con respecto al del anterior líder conservador, Silvela, y la preponderancia de cuestiones como la seguridad nacional como motivadoras de dicho ideario. En la segunda parte, se explica la apelación del gobierno maurista a una ayuda por parte de Alemania, en función de movimientos previos de la diplomacia germana que se había interesado por controlar una parte del Marruecos español, o por conseguir compensaciones en Fernando Po. Finalmente se analiza el intento de Berlín de instrumentalizar al gobierno Maura en el curso de las conversaciones hispano-francesas sobre el Imperio jerifiano.