Poly(amidoamine) (PAMAM) dendrimers were incorporated into a cross-linked poly(vinyl alcohol) (PVA) matrix to improve CO2 separation performance at elevated pressures. An organic metal compound was selected as a cross-linker of PVA. The resulting self-standing PAMAM/ cross-linked PVA membrane containing 41.6 wt% of PAMAM dendrimer had both good pressure tolerance and CO2 permeance. The CO2/H-2 selectivity was almost constant when the CO2 partial pressure in feed gas was from 80 to 560 kPa at 40 degrees C. CO2/H-2 selectivity and CO2 permeance of the membrane were 32 and 1.6 x 10(-12) m(3)(STP)/(m(2) s Pa), respectively, at 560 kPa CO2 partial pressure in the feed gas. Both CO2 permeance and CO2/H-2 selectivity increased as the operation temperature of the membrane was increased from 25 to 60 degrees C. A membrane containing 63.3 wt% of the dendrimer showed CO2/H-2 selectivity and CO2 permeance of 42 and 1.2 x 10(-11) m(3)(STP)/(m(2) s Pa), respectively, at 560 kPa of CO2 partial pressure and 60 degrees C. The PAMAM/ cross-linked PVA hybrid membranes are durable under high pressure operation and thus show promise for applications requiring the separation of CO2 from H-2 under pressurized conditions, such as in the integrated coal gasification combined cycle (IGCC) processes. (c) 2012 Elsevier B.V. All rights reserved.