Catalyzed graphite felt three-dimensional anodes were investigated in direct methanol fuel cells (DMFCs) operated with sulfuric acid supporting electrolyte. With a conventional serpentine channel flow field the preferred anode thickness was 100 mu m, while a novel flow-by anode showed the best performance with a thickness of 200-300 mu m. The effects of altering the methanol concentration, anolyte flow rate and operating temperature on the fuel cell superficial power density were studied by full (2(3) + 1) factorial experiments on a cell with anode area of 5 cm(2) and excess oxidant O-2 at 200 kPa(abs). For operation in the flow-by mode with 2 M methanol at 2 cm(3) min(-1) and 353 K the peak power density was 2380W m(-2) with a PtRuMo anode catalyst, while a PtRu catalyst yielded 2240W m(-2) under the same conditions. (C) 2009 Elsevier B.V. All rights reserved.